Cleanup: Editors/Space/UV-Edit, Clang-Tidy else-after-return fixes

This addresses warnings from Clang-Tidy's `readability-else-after-return`
rule in the `source/blender/editors/uv_edit` module.

No functional changes.

source/blender/editors/uvedit/uvedit_ops.c

@@ -998,9 +998,7 @@ static int uv_remove_doubles_exec(bContext *C, wmOperator *op)
   if (RNA_boolean_get(op->ptr, "use_unselected")) {
     return uv_remove_doubles_to_unselected(C, op);
   }
-  else {
-    return uv_remove_doubles_to_selected(C, op);
-  }
+  return uv_remove_doubles_to_selected(C, op);
 }
 
 static void UV_OT_remove_doubles(wmOperatorType *ot)