add: Variable declarations test.

CanonSharp.Pascal/Parser/GrammarParserBase.cs

@@ -9,7 +9,9 @@ namespace CanonSharp.Pascal.Parser;
 public abstract class GrammarParserBuilder
 {
     protected static IParser<LexicalToken, LexicalToken> Keyword(string value)
-        => Satisfy<LexicalToken>(token => token.TokenType == LexicalTokenType.Keyword && token.LiteralValue == value);
+        => Satisfy<LexicalToken>(token =>
+            token.TokenType == LexicalTokenType.Keyword &&
+            token.LiteralValue.Equals(value, StringComparison.OrdinalIgnoreCase));
 
     protected static IParser<LexicalToken, LexicalToken> Operator(string value)
         => Satisfy<LexicalToken>(token => token.TokenType == LexicalTokenType.Operator && token.LiteralValue == value);