fix: use dfn instead of code tag (#36640)

* Use dfn tags

* remove misused <dfn> tags

* Revert "remove misused <dfn> tags"

This reverts commit b24968a968.

* Update curriculum/challenges/english/01-responsive-web-design/basic-html-and-html5/fill-in-the-blank-with-placeholder-text.english.md

Co-Authored-By: Randell Dawson <5313213+RandellDawson@users.noreply.github.com>

* Make "array" lowercase

Co-Authored-By: Randell Dawson <5313213+RandellDawson@users.noreply.github.com>

* Fix dfn usage

* Address last dfn tags

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/functional-programming/avoid-mutations-and-side-effects-using-functional-programming.english.md

@@ -11,7 +11,7 @@ If you haven't already figured it out, the issue in the previous challenge was w
 This is a small example of a much larger pattern - you call a function on a variable, array, or an object, and the function changes the variable or something in the object.
 One of the core principles of functional programming is to not change things. Changes lead to bugs. It's easier to prevent bugs knowing that your functions don't change anything, including the function arguments or any global variable.
 The previous example didn't have any complicated operations but the <code>splice</code> method changed the original array, and resulted in a bug.
-Recall that in functional programming, changing or altering things is called <code>mutation</code>, and the outcome is called a <code>side effect</code>. A function, ideally, should be a <code>pure function</code>, meaning that it does not cause any side effects.
+Recall that in functional programming, changing or altering things is called <dfn>mutation</dfn>, and the outcome is called a <dfn>side effect</dfn>. A function, ideally, should be a <dfn>pure function</dfn>, meaning that it does not cause any side effects.
 Let's try to master this discipline and not alter any variable or object in our code.
 </section>
 

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/functional-programming/combine-two-arrays-using-the-concat-method.english.md

@@ -7,7 +7,7 @@ forumTopicId: 301229
 
 ## Description
 <section id='description'>
-<code>Concatenation</code> means to join items end to end. JavaScript offers the <code>concat</code> method for both strings and arrays that work in the same way. For arrays, the method is called on one, then another array is provided as the argument to <code>concat</code>, which is added to the end of the first array. It returns a new array and does not mutate either of the original arrays. Here's an example:
+<dfn>Concatenation</dfn> means to join items end to end. JavaScript offers the <code>concat</code> method for both strings and arrays that work in the same way. For arrays, the method is called on one, then another array is provided as the argument to <code>concat</code>, which is added to the end of the first array. It returns a new array and does not mutate either of the original arrays. Here's an example:
 
 ```js
 [1, 2, 3].concat([4, 5, 6]);

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/functional-programming/introduction-to-currying-and-partial-application.english.md

@@ -7,7 +7,7 @@ forumTopicId: 301232
 
 ## Description
 <section id='description'>
-The <code>arity</code> of a function is the number of arguments it requires. <code>Currying</code> a function means to convert a function of N <code>arity</code> into N functions of <code>arity</code> 1.
+The <dfn>arity</dfn> of a function is the number of arguments it requires. <dfn>Currying</dfn> a function means to convert a function of N arity into N functions of arity 1.
 In other words, it restructures a function so it takes one argument, then returns another function that takes the next argument, and so on.
 Here's an example:
 
@@ -29,7 +29,7 @@ const curried = x => y => x + y
 curried(1)(2) // Returns 3
 ```
 
-This is useful in your program if you can't supply all the arguments to a function at one time. You can save each function call into a variable, which will hold the returned function reference that takes the next argument when it's available. Here's an example using the <code>curried</code> function in the example above:
+This is useful in your program if you can't supply all the arguments to a function at one time. You can save each function call into a variable, which will hold the returned function reference that takes the next argument when it's available. Here's an example using the curried function in the example above:
 
 ```js
 // Call a curried function in parts:
@@ -37,7 +37,7 @@ var funcForY = curried(1);
 console.log(funcForY(2)); // Prints 3
 ```
 
-Similarly, <code>partial application</code> can be described as applying a few arguments to a function at a time and returning another function that is applied to more arguments.
+Similarly, <dfn>partial application</dfn> can be described as applying a few arguments to a function at a time and returning another function that is applied to more arguments.
 Here's an example:
 
 ```js

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/functional-programming/understand-functional-programming-terminology.english.md

@@ -10,10 +10,10 @@ forumTopicId: 301240
 The FCC Team had a mood swing and now wants two types of tea: green tea and black tea. General Fact: Client mood swings are pretty common.
 With that information, we'll need to revisit the <code>getTea</code> function from last challenge to handle various tea requests. We can modify <code>getTea</code> to accept a function as a parameter to be able to change the type of tea it prepares. This makes <code>getTea</code> more flexible, and gives the programmer more control when client requests change.
 But first, let's cover some functional terminology:
-<code>Callbacks</code> are the functions that are slipped or passed into another function to decide the invocation of that function. You may have seen them passed to other methods, for example in <code>filter</code>, the callback function tells JavaScript the criteria for how to filter an array.
-Functions that can be assigned to a variable, passed into another function, or returned from another function just like any other normal value, are called <code>first class</code> functions. In JavaScript, all functions are <code>first class</code> functions.
-The functions that take a function as an argument, or return a function as a return value are called <code>higher order</code> functions.
-When the functions are passed in to another function or returned from another function, then those functions which gets passed in or returned can be called a <code>lambda</code>.
+<dfn>Callbacks</dfn> are the functions that are slipped or passed into another function to decide the invocation of that function. You may have seen them passed to other methods, for example in <code>filter</code>, the callback function tells JavaScript the criteria for how to filter an array.
+Functions that can be assigned to a variable, passed into another function, or returned from another function just like any other normal value, are called <dfn>first class</dfn> functions. In JavaScript, all functions are first class functions.
+The functions that take a function as an argument, or return a function as a return value are called <dfn>higher order</dfn> functions.
+When the functions are passed in to another function or returned from another function, then those functions which gets passed in or returned can be called a <dfn>lambda</dfn>.
 </section>
 
 ## Instructions

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/functional-programming/use-the-map-method-to-extract-data-from-an-array.english.md

@@ -9,7 +9,7 @@ forumTopicId: 18214
 <section id='description'>
 So far we have learned to use pure functions to avoid side effects in a program. Also, we have seen the value in having a function only depend on its input arguments.
 This is only the beginning. As its name suggests, functional programming is centered around a theory of functions.
-It would make sense to be able to pass them as arguments to other functions, and return a function from another function. Functions are considered <code>First Class Objects</code> in JavaScript, which means they can be used like any other object. They can be saved in variables, stored in an object, or passed as function arguments.
+It would make sense to be able to pass them as arguments to other functions, and return a function from another function. Functions are considered <dfn>first class objects</dfn> in JavaScript, which means they can be used like any other object. They can be saved in variables, stored in an object, or passed as function arguments.
 Let's start with some simple array functions, which are methods on the array object prototype. In this exercise we are looking at <code>Array.prototype.map()</code>, or more simply <code>map</code>.
 Remember that the <code>map</code> method is a way to iterate over each item in an array. It creates a new array (without changing the original one) after applying a callback function to every element.
 </section>