[4.3] Deprecate unused language strings (#40466)

These language strings are not used in Joomla 4. They were added to address an issue with #31884 but then the entire view was removed with #32933

Test either by code review or simply edit one of the strings and see if the edited string is rendered either when you go to com_users and edit a user profile or when you click on your own username from the edit account link in the dropdown in the top right

Author: brianteeman

administrator/language/en-GB/com_admin.ini

@@ -4,10 +4,15 @@
 ; Note : All ini files need to be saved as UTF-8
 
 COM_ADMIN="System Information"
+; Deprecated, will be removed with 5.0
 COM_ADMIN_A11Y_SETTINGS_FIELDSET_LABEL="Accessibility Settings"
+; Deprecated, will be removed with 5.0
 COM_ADMIN_A11Y_SETTINGS_FIELD_CONTRAST="High Contrast"
+; Deprecated, will be removed with 5.0
 COM_ADMIN_A11Y_SETTINGS_FIELD_FONTSIZE="Increase Font Size"
+; Deprecated, will be removed with 5.0
 COM_ADMIN_A11Y_SETTINGS_FIELD_HIGHLIGHT="Highlight Links"
+; Deprecated, will be removed with 5.0
 COM_ADMIN_A11Y_SETTINGS_FIELD_MONOCHROME="Monochrome"
 COM_ADMIN_ALPHABETICAL_INDEX="Alphabetical Index"
 COM_ADMIN_CACHE_DIRECTORY="(Cache folder)"