fix: Replace user-visible strings of 'Groupchat' with 'Group Chat'

gajim/data/gui/groupchat_manage.ui

@@ -157,7 +157,7 @@
                 <property name="sensitive">False</property>
                 <property name="can-focus">True</property>
                 <property name="receives-default">False</property>
-                <property name="tooltip-text" translatable="yes">Destroy Groupchat…</property>
+                <property name="tooltip-text" translatable="yes">Destroy Group Chat…</property>
                 <signal name="clicked" handler="_on_destroy_clicked" swapped="no"/>
                 <child>
                   <object class="GtkImage">

gajim/gtk/groupchat_details.py

@@ -51,7 +51,7 @@ def __init__(self,
         self.set_type_hint(Gdk.WindowTypeHint.DIALOG)
         self.set_resizable(True)
         self.set_default_size(-1, 600)
-        self.set_title(_('Groupchat Details'))
+        self.set_title(_('Group Chat Details'))
 
         self.account = contact.account
         self._client = app.get_client(contact.account)