Stabilize disable_all_formatting

[rchaser53]

related: #3197, #3388

This options is a very simple and no bugs are reported.
So I think this options can be stabilized only tests addition.

[topecongiro]

I would rather deprecate disable_all_formatting rather than stabilize it as we have ignore which is more flexible.

[rchaser53]

I also think ignore is better than disable_all_formatting.
A good disable_all_formatting's points better than ignore is that can ignore every file.
But we can do same thing without disable_all_formatting option. Do not use rustfmt.
If we want to switch to use or not dynamically, just use shell.

Should I change the PR Stabilize disable_all_formatting to Deprecate disable_all_formatting?

cc: @nrc @scampi

[topecongiro]

Originally disable_all_formatting was added to work around a not-so-good integration between an editor and rustfmt (cc #1297). I think the option is useful in that respect.

Other than replacing disable_all_formatting, ignore is useful when you have submodules in your crate that you do not want rustfmt to touch. A canonical example https://github.com/rust-lang/rust.

Should I change the PR Stabilize disable_all_formatting to Deprecate disable_all_formatting?

Before deprecating disable_all_formatting, I prefer to stabilize ignore first. It is blocked by #3413, but currently I do not have time to work on it. @rchaser53 If you want to push this further, it would be awesome if you could take it over and implement the feature (and add some tests, if possible)!

[rchaser53]

I understand the context of disable_all_formatting.
Ok. I take #3413 over.

[topecongiro]

@rchaser53 Thanks!

[topecongiro]

Closing this as disable_all_formatting should be deprecated in favor of ignore (see #3481 (comment)). @rchaser53 thank you for all the work (including many other PRs to rustfmt)!

[Stargateur]

Warning: can't set ignore = IgnoreList { path_set: {"/"}, rustfmt_toml_path: "" }, unstable features are only available in nightly channel.

This should be an error - -, this was really unexpected that it format anyway !