Missing trailing newlines for mocks

Author: my-tien

test/image/mocks/zzz_date_axes-ticklabelstep-drawminorticklabel.json

@@ -228,4 +228,4 @@
       "drawminorticklabel": -3
     }
   }
-}
+}

test/image/mocks/zzz_date_axes_period_drawminorticklabel.json

@@ -221,4 +221,4 @@
       "drawminorticklabel": 5
     }
   }
-}
+}