Fix typos with codespell

Using codespell 1.15.0.

Method:
```
$ cat > ../godot-word-whitelist.txt << EOF
ang
curvelinear
doubleclick
leapyear
lod
merchantibility
nd
numer
ois
ony
que
seeked
synching
te
uint
unselect
webp
EOF

$ codespell -w -q 3 -I ../godot-word-whitelist.txt --skip="./thirdparty,*.po"
$ git diff // undo unwanted changes
```

editor/animation_track_editor.cpp

@@ -3520,7 +3520,7 @@ void AnimationTrackEditor::_update_tracks() {
 void AnimationTrackEditor::_animation_changed() {
 
 	if (animation_changing_awaiting_update) {
-		return; //all will be updated, dont bother with anything
+		return; //all will be updated, don't bother with anything
 	}
 
 	if (key_edit && key_edit->setting) {