fix(editor): Copy Reference and Paste as Plain Text in the editor's Copy / Paste Special menu (#1333)

The editor's Copy / Paste Special submenu only had Copy Path and Paste from History, so a class's fully qualified name couldn't be copied from the context menu although Copy Reference exists as an action. It now lists Copy Reference, Paste as Plain Text and Paste from History; the file path stays in the editor tab's Copy Path/Reference menu.

Fixes #1261

src/editor/core/controller.ts

@@ -685,7 +685,8 @@ export class EditorController implements SlotHost {
       {
         label: "Copy / Paste Special",
         submenu: [
-          { label: "Copy Path", run: () => void navigator.clipboard?.writeText(slot.model.path) },
+          { kind: "action", action: "editor.copyReference" },
+          { kind: "action", action: "code.pasteAsPlainText" },
           { kind: "action", action: "code.pasteFromHistory" },
         ],
       },