feat: define problem matcher for panics in VS Code

Now in VS Code "go to next error" (`F8`) will bring you to the source of
a panic.

editors/code/src/tasks.ts

@@ -128,7 +128,7 @@ export async function buildCargoTask(
         name,
         TASK_SOURCE,
         exec,
-        ["$rustc"]
+        ["$rustc", "$rust-panic"]
     );
 }