chore: Translate pressbooks-multi-institution.pot in zh

85% of minimum 25% translated source file: 'pressbooks-multi-institution.pot'
on 'zh'.

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

languages/pressbooks-multi-institution-zh.po

@@ -361,11 +361,11 @@ msgstr "只允许数字。"
 
 #: resources/views/institutions/form.blade.php:284
 msgid "Save Changes"
-msgstr ""
+msgstr "保存更改"
 
 #: resources/views/institutions/index.blade.php:20
 msgid "Add new"
-msgstr ""
+msgstr "新加"
 
 #: resources/views/institutions/totals.blade.php:1
 msgid "Book and User Totals"