i18n(voice): use a label for the imagery area line

"Over {area}" put a country name straight after a preposition, which drops
the article Italian, Portuguese, Spanish and German need ("Sopra Italia",
"Über Schweiz"). Use the label form French and the "In {area}" line already
use. zh-Hant now says 服務器 like the rest of its catalog.

src/i18n/locales/es.json

@@ -3025,7 +3025,7 @@
   "Not drawn: {parts}": "Sin dibujar: {parts}",
   "approximate": "aproximado",
   "{pct}% cloud": "{pct} % de nubes",
-  "Over {area}": "Sobre {area}",
+  "Over {area}": "Zona: {area}",
   "{count} of {total} acquisitions match": {
     "many": "Adquisiciones coincidentes: {count} de {total}",
     "one": "Adquisiciones coincidentes: {count} de {total}",