changed Spanish name in meta.xml to Español (es)

might consider adding an Español (latam) edit next year, but this is
enough for 2.4. We're using "Español (es)" instead of "Castellano"
because our translator prefers it

desktop_version/lang/es/meta.xml

@@ -3,7 +3,7 @@
     <active>1</active>
 
     <!-- should be lowercase because menu style, and should be in the language itself -->
-    <nativename>español</nativename>
+    <nativename>español (es)</nativename>
 
     <!-- English translation by X -->
     <credit>Traducción al español de Felipe Mercader y Sara Marín</credit>