Anim UI: Playback Sync menu improvement

Relabel the Playback Synchronisation menu so that it's clear:
- what does happen (instead of describing what does //not// happen), and
- that the synchronisation options don't just affect audio.

The changes are:
- Change label from "Audio" to "Sync"
- Change the labels of the sync enum:
    - No Sync → Play Every Frame
    - Frame Dropping stays the same
    - AV-sync → Sync to Audio

The "Audio" label has moved one option down, as that option does
actually relate to audio.

Reviewed By: looch, Severin, HooglyBoogly, campbellbarton

Differential Revision: https://developer.blender.org/D9269

release/scripts/startup/bl_ui/space_time.py

@@ -241,8 +241,8 @@ class TIME_PT_playback(TimelinePanelButtons, Panel):
         screen = context.screen
         scene = context.scene
 
-        col = layout.column()
-        col.prop(scene, "sync_mode", text="Audio")
+        layout.prop(scene, "sync_mode", text="Sync")
+        col = layout.column(heading="Audio")
         col.prop(scene, "use_audio_scrub", text="Scrubbing")
         col.prop(scene, "use_audio", text="Mute")
 

source/blender/makesrna/intern/rna_scene.c

@@ -7359,9 +7359,9 @@ void RNA_def_scene(BlenderRNA *brna)
   };
 
   static const EnumPropertyItem sync_mode_items[] = {
-      {0, "NONE", 0, "No Sync", "Do not sync, play every frame"},
+      {0, "NONE", 0, "Play Every Frame", "Do not sync, play every frame"},
       {SCE_FRAME_DROP, "FRAME_DROP", 0, "Frame Dropping", "Drop frames if playback is too slow"},
-      {AUDIO_SYNC, "AUDIO_SYNC", 0, "AV-sync", "Sync to audio playback, dropping frames"},
+      {AUDIO_SYNC, "AUDIO_SYNC", 0, "Sync to Audio", "Sync to audio playback, dropping frames"},
       {0, NULL, 0, NULL, NULL},
   };