4.0.0

• Mark package support as LTS mode instead of maintenance mode.
• Add embedded language support.
• Add JSONC support for configuration files.
• Generate vscode.TextDocument mocks for document service output.
• Switch LiteTextDocument to vscode.TextDocument across the package.
• Allow the package to query embedded and builtin languages when extensions supply a vscode.ExtensionContext.
• Change contribution logic to prioritise a supplied extension context instead of restricting contributions to that extension.
• Export ContributorData - a utility for statically resolving language and grammar contributions.
• Patch findLanguageIdFromScopeName grammar priority to match core behaviour.
• Update API documentation to match 4.0.0.