parser: disallow having builtin type as type names for enum, sum type and alias

[Delta456]

Closes #18957

🤖 Generated by Copilot at 39926c5

This pull request enhances the parser's validation of user-defined type names and adds tests for error messages. It prevents name collisions with built-in types for enum, sum type, and type alias declarations.

🤖 Generated by Copilot at 39926c5

• Prevent name collisions between user-defined types and built-in types by adding more invalid type indices to the parser checks (link, link, link)
• Add test files and source code for the error messages when a type alias, an enum, or a sum type name conflicts with a built-in type name, such as string, rune, or map (link, link, link, link, link, link)