valw: edit shots in Noctalia's annotator

modules/home/home-valw.ulu.nix

@@ -8,7 +8,11 @@
       programs.valw = {
         enable = true;
         # Checked by valw itself when the configuration is built.
-        settings.capture.window_shadow = true;
+        settings = {
+          capture.window_shadow = true;
+          # Noctalia's annotator, in the shell's theme (saves a new file).
+          editor.backend = "noctalia";
+        };
         # A bar button, the toolbar as a Noctalia panel, a control-center tile.
         noctalia.enable = true;
       };