Show notification while SSR is in progress

Ideally we would (a) show progress and (b) allow cancellation, but at least now there's some indication to the user that something is happening.

editors/code/src/commands.ts

@@ -171,9 +171,15 @@ export function ssr(ctx: Ctx): Cmd {
         const request = await vscode.window.showInputBox(options);
         if (!request) return;
 
+        vscode.window.withProgress({
+            location: vscode.ProgressLocation.Notification,
+            title: "Structured search replace in progress...",
+            cancellable: false,
+        }, async (_progress, _token) => {
             const edit = await client.sendRequest(ra.ssr, { query: request, parseOnly: false });
 
             await vscode.workspace.applyEdit(client.protocol2CodeConverter.asWorkspaceEdit(edit));
+        });
     };
 }