Add mts and cts file extension aliases (#2936)

Resolves #2936

Author: littlespex

CHANGELOG.md

@@ -8,6 +8,7 @@ title: Changelog
 
 - `@inline` now functions when referencing tuple types, #2932.
 - `@link` links to the current page are now rendered, #2934.
+- `@includeCode` now supports regions in TypeScript files with `.mts` and `.cts` file extensions, #2935.
 - Aliased symbols (re-exports) are now resolved before checking if they are excluded/external, #2937.
 
 ## v0.28.2 (2025-04-07)

src/lib/converter/plugins/IncludePlugin.ts

@@ -428,3 +428,5 @@ regionTagREsByExt["php"] = regionTagREsByExt["cs"];
 regionTagREsByExt["ps1"] = regionTagREsByExt["cs"];
 regionTagREsByExt["py"] = regionTagREsByExt["cs"];
 regionTagREsByExt["js"] = regionTagREsByExt["ts"];
+regionTagREsByExt["mts"] = regionTagREsByExt["ts"];
+regionTagREsByExt["cts"] = regionTagREsByExt["ts"];

src/lib/utils/highlighter.tsx

@@ -2,7 +2,8 @@ import * as shiki from "@gerrit0/mini-shiki";
 import { JSX, unique } from "#utils";
 import assert from "assert";
 
-const aliases = new Map<string, string>();
+const tsAliases: [string, string][] = [["mts", "typescript"], ["cts", "typescript"]];
+const aliases = new Map<string, string>(tsAliases);
 for (const lang of shiki.bundledLanguagesInfo) {
     for (const alias of lang.aliases || []) {
         aliases.set(alias, lang.id);
@@ -175,7 +176,7 @@ export function getSupportedThemes(): string[] {
 
 export function isLoadedLanguage(lang: string): boolean {
     return (
-        plaintextLanguages.includes(lang) || ignoredLanguages?.includes(lang) || highlighter?.supports(lang) || false
+        isSupportedLanguage(lang) || highlighter?.supports(lang) || false
     );
 }