extensions/typescript-language-features/src/typeScriptServiceClientHost.ts/TypeScriptServiceClientHost/registerExtensionLanguageProvider
class TypeScriptServiceClientHost:	private registerExtensionLanguageProvider(description: LanguageDescription, onCompletionAccepted: (item: vscode.CompletionItem) => void) {
		const manager = new LanguageProvider(this.client, description, this.commandManager, this.client.telemetryReporter, this.typingsStatus, this.fileConfigurationManager, onCompletionAccepted);
		this.languages.push(manager);
		this._register(manager);
		this.languagePerId.set(description.id, manager);
	}