Blender Git Commit Log

Cleanup: Add/use function to disable buttons with a disabled hint

We do this in a couple of places, so it's worth having the logic wrapped
into a function.
Also, the only way to set the disabled hint for a button from outside of
`interface/` was through `UI_block_lock_set()`/`UI_block_lock_clear()`,
for which the usage isn't obvious when you just try to disable a single
button.