feat: add normal and bold to StacFontWeight

[Abdalqader27]

Description

• Introduced normal and bold font weight options to the StacFontWeight enum.
• These additions allow for more common and intuitive font weight specifications, aligning with standard CSS and design practices.
• The generated code for StacTextStyle has also been updated to include these new enum values.

Note:

  /// The default font weight.
  static const FontWeight normal = w400;

  /// A commonly used font weight that is heavier than normal.
  static const FontWeight bold = w700;

Related Issues

Closes #259

Type of Change

• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to change)
• Code refactor
• Build configuration change
• Documentation
• Chore

[CLAassistant]

All committers have signed the CLA.

[divyanshub024]

Thank you for your contribution @Abdalqader27 💯