reuse annotate doesn’t use --style if file extension isn’t recognised

[Freso]

Test case

With reuse init already run and where "CC0-1.0" is one of the used licenses:

touch test.txt
reuse annotate --copyright "me!" --license CC0-1.0 --style python ./test.txt

Expected outcome

test.txt would have a Python style header indicating "me!" as the author and CC0-1.0 as the license.

Actual outcome

reuse annotate: error: The following files do not have a recognised file extension. Please use --style, --force-dot-license, --fallback-dot-license, or --skip-unrecognised:

test.txt

Nothing is written to test.txt

Enviroment

> reuse --version
reuse 3.0.1
> distro
Name: Arch Linux
Version: rolling (n/a)
Codename: n/a

[Freso]

Oh, looks like this may be a partial duplicate of #902 and already have a fix waiting in #909 – curious that neither of those showed in my searches for previous reports. Ah well.

Not sure if you want to extract the first part of #902 into this one and then have #902 be only about Cargo.lock files, or if this one should just be closed as a duplicate.