chore: Translate pressbooks-aldine.pot in es

84% of minimum 25% translated source file: 'pressbooks-aldine.pot'
on 'es'.

Sync of partially translated files: 
untranslated content is included with an empty translation 
or source language content depending on file format

languages/pressbooks-aldine-es_ES.po

@@ -589,7 +589,7 @@ msgstr "Ver el catálogo completo"
 
 #: partials/content-none.php:14
 msgid "Nothing Found"
-msgstr ""
+msgstr "No se ha encontrado nada"
 
 #. translators: 1: link to WP admin new post page.
 #: partials/content-none.php:27