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

31% 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

@@ -142,19 +142,19 @@ msgstr "封面"
 
 #: src/Views/AssignBooksTable.php:34
 msgid "Title"
-msgstr ""
+msgstr "标题"
 
 #: src/Views/AssignBooksTable.php:35 src/Views/AssignUsersTable.php:40
 #: src/Views/BookList.php:27 src/Views/UserList.php:51
 #: resources/views/institutions/form.blade.php:49
 #: resources/views/partials/filters/institutions/content.blade.php:3
 #: resources/views/partials/filters/institutions/tab.blade.php:3
 msgid "Institution"
-msgstr ""
+msgstr "机构"
 
 #: src/Views/AssignBooksTable.php:36
 msgid "Book Administrators"
-msgstr ""
+msgstr "书籍管理员"
 
 #: src/Views/AssignUsersTable.php:37
 msgid "Username"