minor copyedit on pm a/r button

app/assets/javascripts/discourse/widgets/private-message-map.js.es6

@@ -157,8 +157,6 @@ export default createWidget("private-message-map", {
       this.attach("button", {
         action: "toggleEditing",
         label: "private_message_info.edit",
-        icon: "user",
-        iconRight: true,
         className: "btn add-remove-participant-btn"
       })
     ];

config/locales/client.en.yml

@@ -1129,8 +1129,8 @@ en:
 
     private_message_info:
       title: "Message"
-      invite: "Invite Others..."
-      edit: "Add or remove"
+      invite: "Invite Others ..."
+      edit: "Add or Remove ..."
       leave_message: "Do you really want to leave this message?"
       remove_allowed_user: "Do you really want to remove {{name}} from this message?"
       remove_allowed_group: "Do you really want to remove {{name}} from this message?"