Some slight grammar fixes in JSON Parser and Printer (#10968)

* some slight grammar fixes

* suggestion from Aurel

Co-authored-by: Aurel <[email protected]>

* fix for printer aswell

* taking a suggestion from kLabz

---------

Co-authored-by: Aurel <[email protected]>

std/haxe/format/JsonParser.hx

@@ -23,7 +23,7 @@
 package haxe.format;
 
 /**
-	An implementation of JSON parser in Haxe.
+	An implementation of a JSON parser in Haxe.
 
 	This class is used by `haxe.Json` when native JSON implementation
 	is not available.

std/haxe/format/JsonPrinter.hx

@@ -23,7 +23,7 @@
 package haxe.format;
 
 /**
-	An implementation of JSON printer in Haxe.
+	An implementation of a JSON printer in Haxe.
 
 	This class is used by `haxe.Json` when native JSON implementation
 	is not available.
@@ -34,7 +34,7 @@ class JsonPrinter {
 	/**
 		Encodes `o`'s value and returns the resulting JSON string.
 
-		If `replacer` is given and is not null, it is used to retrieve
+		If `replacer` is given and is not null, it is used to retrieve the
 		actual object to be encoded. The `replacer` function takes two parameters,
 		the key and the value being encoded. Initial key value is an empty string.