refactor(grammar): redefine NAME and NAME_WITH_RESERVED tokens in Fqn…

[ayush-shah]

… grammar for improved parsing

• Updated NAME token to allow more characters and disallow certain literals.
• Modified NAME_WITH_RESERVED token to remove internal dot requirement and allow any characters within quotes.
• Introduced new fragments for escape sequences and character definitions to enhance grammar clarity.

Describe your changes:

Fixes

I worked on ... because ...

Type of change:

• [ ] Bug fix
• [ ] Improvement
• [ ] New feature
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Documentation

Checklist:

• [x] I have read the CONTRIBUTING document.
• [ ] My PR title is Fixes <issue-number>: <short explanation>
• [ ] I have commented on my code, particularly in hard-to-understand areas.
• [ ] For JSON Schema changes: I updated the migration scripts or explained why it is not needed.