#10026 Implement DocumentSymbolProviderMetadata

[ndoschek]

What it does

This PR adds the implementation for DocumentSymbolProviderMetadata and uses label in MonacoOutlineContribution:

• Introduce DocumentSymbolProviderMetadata interface in theia.d.ts
• Adapt register functions to pass on optional metadata
• Adapt the MonacoOutlineContribution and use metadata label or plugin's displayName as root node if multiple providers are registered (aligned to behavior in VSCode)
• Remove Theia's custom DocumentSymbolProvider for 'launch.json' files and reuse VSCode's provider (available via vscode-builtin-configuration-editing)

Contributed on behalf of STMicroelectronics

Signed-off-by: Nina Doschek ndoschek@eclipsesource.com

Fixes #10026

How to test

1. Open a launch.json file in your workspace (e.g. https://github.com/eclipse-theia/theia/blob/master/.vscode/launch.json)
2. Open the Outline View via menu View > Outline
3. Comparable to VSCode, there are two providers registered:
   1. The plugin vscode-builtin-json-language-features
      Provides the JSON document outline under the root node JSON Language Features (built-in)
   2. The plugin vscode-builtin-configuration-editing
      Provides all launch configs as document symbols under the root node Launch Targets.
4. It is shown that either the metadata label (in case of 3.ii.) is used as root node display name or if not available the plugin display name (in case of 3.i.).

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[msujew]

@colin-grant-work Can you tell, whether this change is in conflict with your changes for the monaco uplift? If so, we should probably wait for your uplift to finish before merging/reviewing other monaco related changes.

[colin-grant-work]

@msujew, at a glance, it looks like it'll only require modifying the references to monaco.Range to use imports to be compatible with the uplift, so I don't think it needs to wait - fixing the uplift once this is merged will be straightforward.

[msujew]

The changes are looking really good. Happy that we're able to remove the adhoc document symbol provider for the launch.json :)

• Opening the launch.json file shows two distinct document symbol providers
• Other *.json files show the usual json symbols
• Symbols for code (tested with *.ts) work as expected

A minor comment before this is ready to be merged.

[msujew]

Thanks, looking good!