use new 'edit message' strings

src/main/res/values/strings.xml

@@ -41,6 +41,8 @@
     <string name="later">Later</string>
     <!-- "Resend" means "Sending the selected message(s) again to the same chat". The string is used in a menu and should be as short as possible. Resending may be needed after failures or to repost old messages to new members. -->
     <string name="resend">Resend</string>
+    <string name="edited">Edited</string>
+    <string name="edit_message">Edit Message</string>
     <!-- Verb "to archive", as in "put a chat in the archive", not a noun "The Archive". -->
     <string name="archive">Archive</string>
     <!-- Verb "to unarchive", as in "remove a chat from the archive", opposite of the previous string -->