Add missing terminators + other corrections (#23502)

* Add missing terminators + other corrections

Missing terminators were added and for loop formatting was corrected. Even though terminators are optional, they can often confuse beginners. Also, a typo and a grammatical error was corrected.

* fix: formatting

guide/english/javascript/loops/for-in-loop/index.md

@@ -1,11 +1,12 @@
 ---
 title: For...In Loop
 ---
-The `for...in` statement iterates over the enumerable properties of an object, in arbitrary order. For each distinct property, statements can be executed.
-
-    for (variable in object) {
-    ...
-    }
+The `for...in` statement iterates over the enumerable properties of an object, in an arbitrary order. For each distinct property, statements can be executed.
+```js
+for (variable in object) {
+  ...
+}
+```
 
 | Required/Optional | Parameter | Description |
 |-------------------|-----------|----------------------------------------------------------------------|
@@ -15,57 +16,57 @@ The `for...in` statement iterates over the enumerable properties of an object, i
 
 
 ## Examples
+```js
+// Initialize object.
+var a = { "a": "Athens", "b": "Belgrade", "c": "Cairo" };
 
-    // Initialize object.
-    a = { "a": "Athens", "b": "Belgrade", "c": "Cairo" }
+// Iterate over the properties.
+var s = "";
+for (var key in a) {
+    s += key + ": " + a[key];
+    s += "<br />";
+}
+document.write (s);
 
-    // Iterate over the properties.
-    var s = ""
-    for (var key in a) {
-        s += key + ": " + a[key];
-        s += "<br />";
-        }
-    document.write (s);
+// Output:
+// a: Athens
+// b: Belgrade
+// c: Cairo
 
-    // Output:
-    // a: Athens
-    // b: Belgrade
-    // c: Cairo
+// Initialize the array.
+var arr = new Array("zero", "one", "two");
 
-    // Initialize the array.
-    var arr = new Array("zero", "one", "two");
+// Add a few expando properties to the array.
+arr["orange"] = "fruit";
+arr["carrot"] = "vegetable";
 
-    // Add a few expando properties to the array.
-    arr["orange"] = "fruit";
-    arr["carrot"] = "vegetable";
+// Iterate over the properties and elements.
+var s = "";
+for (var key in arr) {
+    s += key + ": " + arr[key];
+    s += "<br />";
+}
 
-    // Iterate over the properties and elements.
-    var s = "";
-    for (var key in arr) {
-        s += key + ": " + arr[key];
-        s += "<br />";
-    }
+document.write (s);
 
-    document.write (s);
+// Output:
+//   0: zero
+//   1: one
+//   2: two
+//   orange: fruit
+//   carrot: vegetable
 
-    // Output:
-    //   0: zero
-    //   1: one
-    //   2: two
-    //   orange: fruit
-    //   carrot: vegetable
-    
-    // Efficient way of getting an object's keys using an expression within the for-in loop's conditions
-    var myObj = {a: 1, b: 2, c:3}, myKeys = [], i=0;
-    for (myKeys[i++] in myObj);
-    
-    document.write(myKeys);
-    
-    //Output:
-    //   a
-    //   b
-    //   c
+// Efficient way of getting an object's keys using an expression within the for-in loop's conditions
+var myObj = {a: 1, b: 2, c:3}, myKeys = [], i=0;
+for (myKeys[i++] in myObj);
 
-# Ohter Resources:
+document.write(myKeys);
+
+//Output:
+//   a
+//   b
+//   c
+```
+## Other Resources:
 * [MDN link](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in)
 * [MSDN link](https://msdn.microsoft.com/library/55wb2d34.aspx)