chore(shields): Add missing display-name for existing keymaps (#3048)

app/boards/shields/romac_plus/romac_plus.keymap

@@ -13,6 +13,7 @@
         compatible = "zmk,keymap";
 
         default_layer {
+            display-name = "Default Layer";
 // --------------------------
 // | 7      |  8  |  9      |
 // | 4      |  5  |  6      |
@@ -30,6 +31,7 @@
         };
 
          nav_layer {
+            display-name = "Nav Layer";
 // --------------------------
 // | BT_CLR |  HOME |  PGUP |
 // | _      |  END  |  PGDN |
@@ -46,4 +48,4 @@
              sensor-bindings = <&inc_dec_kp A B>;
          };
     };
-};
+};