In practice it turns out that turning off PCH is pretty
useful when debugging incorrect includes. I didn't want
to add this option initially because of the sheer amount
of copy-pasta that meson requires. But considering that
this is useful and the cost of copying the option a single
time is not too high this seems acceptable.
This adds a meson.format file that mostly mirrors the projects
meson style and a pre-commit hook to enforce this style.
Some low-diff files are formatted.
The API docs build is extremely noisy (#11841) and probably not many
people care about it anyway. Also, they get rebuild on *every* ninja
invocation which is generally a waste of time.
Of course, you can still build the docs via `nix build
.#nix-{internal,external}-api-docs`, which is pretty fast.
