Disable enter key for accepting code completion in Monaco (#30548) (#30558)

Backport #30548 by @silverwind

Fixes https://github.com/go-gitea/gitea/issues/28114 and behaviour
matches vscode on desktop as well.

Co-authored-by: silverwind <me@silverwind.io>

web_src/js/features/codeeditor.js

@@ -112,6 +112,10 @@ export async function createMonaco(textarea, filename, editorOpts) {
     ...other,
   });
 
+  monaco.editor.addKeybindingRules([
+    {keybinding: monaco.KeyCode.Enter, command: null}, // disable enter from accepting code completion
+  ]);
+
   const model = editor.getModel();
   model.onDidChangeContent(() => {
     textarea.value = editor.getValue({preserveBOM: true});