src/vs/workbench/services/textMate/common/TMHelper.ts/ThemeRule/_matchesOne
class ThemeRule:	private static _matchesOne(selectorScope: string, scope: string): boolean {
		const selectorPrefix = selectorScope + '.';
		if (selectorScope === scope || scope.substring(0, selectorPrefix.length) === selectorPrefix) {
			return true;
		}
		return false;
	}