`--language` command line argument is not supported

Hello & thanks for this awesome tool!

The documentation says:

You can override the language detection by passing the --language option.

https://difftastic.wilfred.me.uk/usage.html#language-detection

I can see that this feature was initially added in https://github.com/Wilfred/difftastic/commit/e472acb8050e84c671470421f4fd5c74a9d3b2bd

But when I try to use the language option I get:

$ difft --language yaml <(echo 'hello: world') <(echo 'foo: bar')
error: Found argument '--language' which wasn't expected, or isn't valid in this context

    Did you mean '--list-languages'?

    If you tried to supply `--language` as a value rather than a flag, use `-- --language`

USAGE:
    difft [OPTIONS] OLD-PATH NEW-PATH

For more information try --help

difft --version
Difftastic 0.58.0 (0c92771 2024-05-10, built with rustc 1.65.0)

Maybe it's just a documentation issue :man_shrugging:

Wilfred / difftastic

`--language` command line argument is not supported #712