Summary

This PR redesigns the exception display system to provide a cleaner, more structured, and colorblind-friendly output format.

Key Changes

Display Format Redesign

• Replaced emoji-based layout with pipe-box structure using │ separators
• Type name on first line with caller location when available (e.g., PreconditionError → configure! MyModule.jl:42)
• Aligned labels (Got, Expected, Reason, Hint, Context, etc.) padded to common width
• Color coding: red for type name, yellow for warnings, green for hints
• Dynamic Hint generation for ExtensionError based on weakdeps

Code Refactoring

• Split monolithic _format_user_friendly_error into modular rendering functions:
  • _build_primary_pairs for type-specific field extraction
  • _render_field for consistent field formatting
  • _render_secondary_pairs for optional fields
  • _render_user_location for caller tracking
• Added ANSI styling primitives: _dim, _bold, _red, _yellow, _green
• Improved _format_diagnostic for AmbiguousDescription with human-readable expansions

Documentation Updates

• Updated docs/src/guide/exceptions.md with new display examples
• Updated docs/src/index.md to use showerror instead of println
• Removed context field from ParsingError documentation (was already removed from type)

Test Updates

• Updated all display tests to match new format (e.g., "Suggestion:" → "Hint ")
• Tests verify pipe-box structure, aligned labels, and color coding
• Coverage maintained for all exception types

Benefits

• Better visual hierarchy with consistent spacing and alignment
• Colorblind-friendly (no reliance on emoji colors)
• More scannable with clear section separation
• Easier to maintain with modular rendering functions
• Consistent across all exception types

Testing

All tests in test/suite/exceptions/test_exception_display.jl and test/suite/exceptions/test_exceptions.jl pass.