extensions/typescript-language-features/src/languageFeatures/completions.ts/getScriptKindDetails
function getScriptKindDetails(tsEntry: Proto.CompletionEntry,): string | undefined {
	if (!tsEntry.kindModifiers || tsEntry.kind !== PConst.Kind.script) {
		return;
	}

	const kindModifiers = parseKindModifier(tsEntry.kindModifiers);
	for (const extModifier of PConst.KindModifiers.fileExtensionKindModifiers) {
		if (kindModifiers.has(extModifier)) {
			if (tsEntry.name.toLowerCase().endsWith(extModifier)) {
				return tsEntry.name;
			} else {
				return tsEntry.name + extModifier;
			}
		}
	}
	return undefined;
}