Libmpv doesn't use libmpv video output as default about mpv

[sfan5]

https://github.com/mpv-player/mpv/blob/master/DOCS/client-api-changes.rst

- partially revert the changes from API version 1.27, remove libmpv as
    the default VO and move it to the bottom of the auto-probing order.
    This restores the prior behavior on all platforms other than macOS,
    but still auto selects libmpv/cocoa-cb on macOS if it was built with
    support for cocoa-cb.

[brainrom]

Oops, didn't find. Checked the main changelog, but not separate one.
But why this was reverted?

Then, examples should be fixed, not mpv?

[kasper93]

Let's consolidate the discussion about those changes in #13974 and what should be done to make releases smoother in terms of breaking changes.

Now that it has been released as 0.38, it is too late to change it back.