src/vs/workbench/contrib/snippets/browser/snippetsService.ts/SnippetsService/_addSnippetFile
class SnippetsService:	private _addSnippetFile(uri: URI, source: SnippetSource): IDisposable {
		const ext = resources.extname(uri);
		if (source === SnippetSource.User && ext === '.json') {
			const langName = resources.basename(uri).replace(/\.json/, '');
			this._files.set(uri, new SnippetFile(source, uri, [langName], undefined, this._fileService, this._extensionResourceLoaderService));
		} else if (ext === '.code-snippets') {
			this._files.set(uri, new SnippetFile(source, uri, undefined, undefined, this._fileService, this._extensionResourceLoaderService));
		}
		return {
			dispose: () => this._files.delete(uri)
		};
	}