Sequencer: Restore change menu

It was still used by C-key menu, and is very handy to have
when working on a complex edit files.

Was initially removed by e9d06f0866.

release/scripts/startup/bl_ui/space_sequencer.py

@@ -280,6 +280,30 @@ class SEQUENCER_MT_marker(Menu):
         marker_menu_generic(layout)
 
 
+class SEQUENCER_MT_change(Menu):
+    bl_label = "Change"
+
+    def draw(self, context):
+        layout = self.layout
+        strip = act_strip(context)
+
+        layout.operator_context = 'INVOKE_REGION_WIN'
+
+        layout.operator_menu_enum("sequencer.change_effect_input", "swap")
+        layout.operator_menu_enum("sequencer.change_effect_type", "type")
+        prop = layout.operator("sequencer.change_path", text="Path/Files")
+
+        if strip:
+            stype = strip.type
+
+            if stype == 'IMAGE':
+                prop.filter_image = True
+            elif stype == 'MOVIE':
+                prop.filter_movie = True
+            elif stype == 'SOUND':
+                prop.filter_sound = True
+
+
 class SEQUENCER_MT_frame(Menu):
     bl_label = "Frame"
 
@@ -1305,6 +1329,7 @@ class SEQUENCER_PT_custom_props(SequencerButtonsPanel, PropertyPanel, Panel):
 
 
 classes = (
+    SEQUENCER_MT_change,
     SEQUENCER_HT_header,
     SEQUENCER_MT_editor_menus,
     SEQUENCER_MT_view,