Add toUpperCase function (#2697)

src/mfm/parse/core/syntax-highlighter.ts

@@ -1,4 +1,4 @@
-import { capitalize } from "../../../prelude/string";
+import { capitalize, toUpperCase } from "../../../prelude/string";
 
 function escape(text: string) {
 	return text
@@ -92,7 +92,7 @@ const _keywords = [
 
 const keywords = _keywords
 	.concat(_keywords.map(capitalize))
-	.concat(_keywords.map(k => k.toUpperCase()))
+	.concat(_keywords.map(toUpperCase))
 	.sort((a, b) => b.length - a.length);
 
 const symbols = [

src/prelude/string.ts

@@ -1,3 +1,7 @@
 export function capitalize(s: string): string {
-	return s.charAt(0).toUpperCase() + s.slice(1).toLowerCase();
+	return toUpperCase(s.charAt(0)) + s.slice(1).toLowerCase();
+}
+
+export function toUpperCase(s: string): string {
+	return s.toUpperCase();
 }