Ctrl+T -> Alt+T to change subject. Fixes #4432

data/glade/message_window.glade

@@ -714,7 +714,7 @@
                       <widget class="GtkButton" id="change_subject_button">
                         <property name="visible">True</property>
                         <property name="events">GDK_POINTER_MOTION_MASK | GDK_POINTER_MOTION_HINT_MASK | GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK</property>
-                        <property name="tooltip" translatable="yes">Change the room's subject (Ctrl+T)</property>
+                        <property name="tooltip" translatable="yes">Change the room's subject (Alt+T)</property>
                         <property name="relief">GTK_RELIEF_NONE</property>
                         <property name="response_id">0</property>
                         <child>