feat: add support for feature gates

[GordonSmith]

fixes: #34

[Copilot]

Pull Request Overview

Adds support for recognizing WIT feature‐gate annotations (@unstable, @since, @deprecated) in both unit/integration tests and the TextMate grammar.

• Introduces new unit tests covering basic and comprehensive feature‐gate usage.
• Adds integration tests and snapshot updates for feature‐gate scenarios.
• Extends wit.tmLanguage.json with #feature-gate and #feature-gate-content rules and integrates them into relevant grammar scopes.
• Updates VS Code launch configuration to point at the tests/grammar folder.

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/grammar/unit/feature-gates-test.wit	New unit tests exercising all feature gates
tests/grammar/unit/basic-feature-gates.wit	New basic feature-gate unit test
tests/grammar/integration/feature-gates.wit	Integration test covering world/interface cases
tests/grammar/integration/feature-gates.wit.snap	Updated expected tokenization snapshots
syntaxes/wit.tmLanguage.json	Added feature-gate rules and includes
.vscode/launch.json	Adjusted test path to tests/grammar

Comments suppressed due to low confidence (3)

tests/grammar/unit/basic-feature-gates.wit:1

• [nitpick] The test filename basic-feature-gates.wit is inconsistent with the *-test.wit suffix used elsewhere. Consider renaming it to basic-feature-gates-test.wit for consistency.

// SYNTAX TEST "source.wit" "This tests basic feature gate annotations"

syntaxes/wit.tmLanguage.json:727

• The #resource rule's begin pattern likely does not allow leading whitespace, so indented resource declarations inside interfaces or worlds won’t be matched. Consider updating its regex to ^\\s*\\b(resource) to handle indentation.

{
          "include": "#resource"
        },

.vscode/launch.json:16

• [nitpick] ${workspaceRoot} is deprecated in VS Code launch settings. Replace it with ${workspaceFolder} to align with current recommendations.

"${workspaceRoot}/tests/grammar"

[github-actions]

🎉 This change has been included in wit-idl-v0.3.4 🎉

The release is available on:

• GitHub releases: wit-idl: v0.3.4

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