Remove warnings in JSONParser.kt

1. Mostly added @Suppress("UNCHECKED_CAST") to different casts as they will never fail.
(They will never fail as the stack, on which it is based on, has a specific structure and it is being built by the same function that uses it in the background. This means that even though it wasn't explicitly stated (for the compiler) that this cast can be done, it is being implied by the structure of the stack itself)

2. Changing the variable type of the stack from a var to a val (and with that a constant) as the reference that it contains is never being changed.

3. Fix a spelling mistake from "Expeced" to "Expected".

Author: QuickWrite

src/main/kotlin/JSONParser.kt

@@ -19,7 +19,7 @@ fun jsonParse(input: String): Any? {
 
     var token: JSONLexeme
 
-    var stack = Stack<Any?>()
+    val stack = Stack<Any?>()
 
     while (true) {
         token = lexer.getNext()
@@ -64,17 +64,20 @@ fun jsonParse(input: String): Any? {
                     if (stack.peek() is String) {
                         val name = stack.pop() as String
 
+                        @Suppress("UNCHECKED_CAST")
                         (stack.peek() as HashMap<String, Any?>)[name] = jsonObject
                         continue
                     }
 
                     // Should now be an array
+                    @Suppress("UNCHECKED_CAST")
                     (stack.peek() as ArrayList<Any?>).add(jsonObject)
 
                     state = State.ARRAY
                     continue
                 }
 
+                @Suppress("UNCHECKED_CAST")
                 val map = stack.peek() as HashMap<String, Any?>
 
                 if(map.isNotEmpty()) {
@@ -94,7 +97,7 @@ fun jsonParse(input: String): Any? {
                 token = lexer.getNext()
 
                 if (token.type != COLON) {
-                    throw JSONParserException("Expeced ':' (COLON), but got ${token.type}") // TODO: Better error reporting
+                    throw JSONParserException("Expected ':' (COLON), but got ${token.type}") // TODO: Better error reporting
                 }
 
                 token = lexer.getNext()
@@ -134,17 +137,20 @@ fun jsonParse(input: String): Any? {
                     if (stack.peek() is String) {
                         val name = stack.pop() as String
 
+                        @Suppress("UNCHECKED_CAST")
                         (stack.peek() as HashMap<String, Any?>)[name] = array
 
                         state = State.OBJECT
                         continue
                     }
 
                     // Should now be an array
+                    @Suppress("UNCHECKED_CAST")
                     (stack.peek() as ArrayList<Any?>).add(array)
                     continue
                 }
 
+                @Suppress("UNCHECKED_CAST")
                 val array = stack.peek() as ArrayList<Any?>
 
                 if (array.isNotEmpty()) {