Autocomplete unknown value in set filetype ...

[dmaluka]

unknown is a valid value for the filetype option (and executing set filetype unknown does what is expected: it forces filetype autodetection). So let's add unknown to the autocomplete suggestions for filetype, along with actual filetypes.

[Andriamanitra]

Good change, works as expected.

and executing set filetype unknown does what is expected: it forces filetype autodetection

That's definitely not what I thought it would do, but that's beside the point 😆

[dmaluka]

Help says:

* `filetype`: sets the filetype for the current buffer. Set this option to
   `off` to completely disable filetype detection.

    default value: `unknown`. This will be automatically overridden depending
    on the file you open.

So, it does not explicitly say that unknown gets automatically overridden even when setting it manually with set filetype unknown, but one could guess so. :)

...Hmm, the off value is also documented. And unlike unknown, it doesn't work quite as expected: the filetype does change to off, but the syntax highlighting does not disappear.

[dmaluka]

...Hmm, the off value is also documented. And unlike unknown, it doesn't work quite as expected: the filetype does change to off, but the syntax highlighting does not disappear.

Pushed d64c944 to autocomplete it as well, and pushed #3216 to fix its behavior.