task: Explanations and grammar fixes for all the GoF patterns (#1791)

* Grammatical fixes to command pattern

* Update bridge pattern readme

* Fixes to builder pattern grammar

* Update chain of responsibility

* Improvements to the composite example

* Fixes to headings

* Minor updates to decorator pattern

* Update facade

* Update factory example

* Update factory method

* Update flyweight

* Interpreter explanation

* Update iterator readme

* Add explanation for mediator pattern

* Grammatical fixes to memento

* Grammar fixes for observer

* Update explanation for the prototype pattern

* Proxy pattern grammar fixes

* Update singleton

* Grammar fixes to state pattern

* Grammar fixes for strategy

* Grammar fixes, template method

* Grammar fixes for visitor

* Fix typo

prototype/src/main/java/com/iluwatar/prototype/App.java

@@ -29,7 +29,7 @@ import lombok.extern.slf4j.Slf4j;
  * The Prototype pattern is a creational design pattern in software development. It is used when the
  * type of objects to create is determined by a prototypical instance, which is cloned to produce
  * new objects. This pattern is used to: - avoid subclasses of an object creator in the client
- * application, like the abstract factory pattern does. - avoid the inherent cost of creating a new
+ * application, like the abstract factory pattern, does. - avoid the inherent cost of creating a new
  * object in the standard way (e.g., using the 'new' keyword)
  *
  * <p>In this example we have a factory class ({@link HeroFactoryImpl}) producing objects by