docs: updated documentation of reactive-controllers

[Rajdeepc]

Description

This PR provides a comprehensive update to all reactive controller documentation files, ensuring complete API coverage, accessibility guidance, and practical examples. This addresses the requirements for fully documenting each controller's properties, methods, events, CSS properties, tokens, and accessibility considerations.

Changes

Updated 7 documentation files:

• color-controller.md
• match-media.md
• element-resolution.md
• dependency-manager.md
• pending-state.md
• roving-tab-index.md
• README.md

Added 1 documentation file:

• system-context-controlller.md

What's New

Full API Documentation

• Constructor signatures with parameters
• All properties (types, descriptions)
• All methods (parameters, returns, descriptions)
• Lifecycle hooks and exported symbols

Accessibility

• WCAG compliance guidelines
• ARIA patterns and keyboard interactions
• Screen reader support patterns
• Links to W3C ARIA Authoring Practices and Adobe Accessibility Guidelines

Enhanced Examples

• Added code examples across all controllers
• Real-world use cases (forms, navigation, lazy loading, etc.)
• Integration with other Spectrum Web Components
• All examples include proper ARIA attributes

Other Improvements

• Documented PendingStateController deprecation consideration
• Noted known accessibility issues (SWC-1119, SWC-1255, SWC-459)
• Added comprehensive controller catalog to README
• Links to related resources and specifications

Motivation and context

The existing documentation was missing critical information:

• Incomplete API documentation (missing properties, methods, events)
• Limited or no accessibility guidance
• Basic examples that didn't demonstrate real-world usage patterns
• No links to accessibility team documentation or design specs
• Missing information about component integration patterns
• This update ensures developers have everything they need to implement these controllers correctly and accessibly.

Related issue(s)

• fixes SWC-429

Screenshots (if appropriate)

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Author's checklist

• I have read the CONTRIBUTING and PULL_REQUESTS documents.
• I have reviewed at the Accessibility Practices for this feature, see: Aria Practices
• I have added automated tests to cover my changes.
• I have included a well-written changeset if my change needs to be published.
• I have included updated documentation if my change required it.

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Reviewer's checklist

• Includes a Github Issue with appropriate flag or Jira ticket number without a link
• Includes thoughtfully written changeset if changes suggested include patch, minor, or major features
• Automated tests cover all use cases and follow best practices for writing
• Validated on all supported browsers
• All VRTs are approved before the author can update Golden Hash

Manual review test cases

• Manual Test Case

  1. ✅ No linting errors
  2. ✅ Consistent formatting per workspace conventions
  3. ✅ All internal links verified

Breaking Changes

None - documentation only.

Device review

• Did it pass in Desktop?
• Did it pass in (emulated) Mobile?
• Did it pass in (emulated) iPad?

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Latest commit: 9e6283a

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Pull Request Test Coverage Report for Build 18845086285

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 97.966%

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Totals
Change from base Build 18844771637:	0.0%
Covered Lines:	34259
Relevant Lines:	34788

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💛 - Coveralls

[nikkimk]

Wow! This was quite the undertaking! Overall this is really, really good stuff. If left some comments and suggestions for changes.

[rise-erpelding]

Wow, this was a huge undertaking! The documentation and examples here look great overall, and I learned a lot reading them!

I left a few comments. I also see that there weren't docs for the system context resolution controller, that's probably the primary thing needing adjustment here.

[nikkimk]

Love the "How it works" section of LanguageResolutionController!

I had one more suggestion. Also, do you think we should do SystemContextResolutionController?

[rise-erpelding]

Looks great! Left one comment about the formatting where the system context resolution controller was added in the README, otherwise I think this is good to go!

[caseyisonit]

this is AMAZING! i learned a ton!