src/vs/base/common/mime.ts/getMediaOrTextMime
export function getMediaOrTextMime(path: string): string | undefined {
	const ext = extname(path);
	const textMime = mapExtToTextMimes[ext.toLowerCase()];
	if (textMime !== undefined) {
		return textMime;
	} else {
		return getMediaMime(path);
	}
}