Bugfix. Leave space between classes

spec/muc_messages.js

@@ -218,11 +218,11 @@
                 type: 'groupchat'
             }).c('body').t('I wrote this message!').tree();
             await view.model.onMessage(msg);
+            await u.waitUntil(() => view.el.querySelectorAll('.chat-msg').length);
             expect(view.model.messages.last().occupant.get('affiliation')).toBe('owner');
             expect(view.model.messages.last().occupant.get('role')).toBe('moderator');
             expect(view.el.querySelectorAll('.chat-msg').length).toBe(1);
             expect(sizzle('.chat-msg', view.el).pop().classList.value.trim()).toBe('message chat-msg groupchat moderator owner');
-
             let presence = $pres({
                     to:'romeo@montague.lit/orchard',
                     from:'lounge@montague.lit/romeo',

src/converse-message-view.js

@@ -297,7 +297,7 @@ converse.plugins.add('converse-message-view', {
 
             getRetractionText () {
                 const username = this.model.getDisplayName();
-                let retraction_text = __('A message by %1$s has been retracted', username);
+                let retraction_text = __('%1$s has retracted this message', username);
                 if (this.model.get('type') === 'groupchat') {
                     const retracted_by_mod = this.model.get('moderated_by');
                     if (retracted_by_mod) {
@@ -382,18 +382,19 @@ converse.plugins.add('converse-message-view', {
                 ];
                 if (this.model.get('type') === 'groupchat') {
                     if (this.model.occupant) {
-                        extra_classes += ` ${this.model.occupant.get('role') || ''} ${this.model.occupant.get('affiliation') || ''}`;
+                        extra_classes.push(this.model.occupant.get('role'));
+                        extra_classes.push(this.model.occupant.get('affiliation'));
                     }
                     if (this.model.get('sender') === 'them' && this.model.collection.chatbox.isUserMentioned(this.model)) {
                         // Add special class to mark groupchat messages
                         // in which we are mentioned.
-                        extra_classes += ' mentioned';
+                        extra_classes.push('mentioned');
                     }
                 }
                 if (this.model.get('correcting')) {
-                    extra_classes += ' correcting';
+                    extra_classes.push('correcting');
                 }
-                return extra_classes;
+                return extra_classes.filter(c => c).join(" ");
             }
         });
     }

src/templates/message.html

-<div class="message chat-msg {{{o.type}}}{[ if (o.is_me_message) { ]} chat-msg--action {[ } ]}{{{o.extra_classes}}}"
+<div class="message chat-msg {{{o.type}}} {{{o.extra_classes}}} {[ if (o.is_me_message) { ]} chat-msg--action {[ } ]}"
         data-isodate="{{{o.time}}}" data-msgid="{{{o.msgid}}}" data-from="{{{o.from}}}" data-encrypted="{{{o.is_encrypted}}}">
     {[ if (o.type !== 'headline' && !o.is_me_message) { ]}
     <canvas class="avatar chat-msg__avatar" height="36" width="36"></canvas>