Code complete fixes and changelog

common/syscalls/language.ts

@@ -1,7 +1,7 @@
 import { SysCallMapping } from "../../plugos/system.ts";
 import { parse } from "../markdown_parser/parse_tree.ts";
 import type { ParseTree } from "$sb/lib/tree.ts";
-import { languageFor } from "../languages.ts";
+import { builtinLanguages, languageFor } from "../languages.ts";
 
 export function languageSyscalls(): SysCallMapping {
   return {
@@ -16,5 +16,10 @@ export function languageSyscalls(): SysCallMapping {
       }
       return parse(lang, code);
     },
+    "language.listLanguages": (
+      _ctx,
+    ): string[] => {
+      return Object.keys(builtinLanguages);
+    },
   };
 }