sort: options -C and -c should be mutually exclusive but aren't

[ic3man5]

Fixes #7184 :

$ cargo run sort -Cc
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.10s
     Running `target/debug/coreutils sort -Cc`
error: the argument '--check-silent' cannot be used with '--check[=<check>...]'

Usage: target/debug/coreutils sort [OPTION]... [FILE]...

For more information, try '--help'.
$ echo $?
2

GNU sort:

$ sort -Cc
sort: options '-cC' are incompatible
$ echo $?
2

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/misc/usage_vs_getopt. tests/misc/usage_vs_getopt is passing on 'main'. Maybe you have to rebase?

[sylvestre]

Could you please add a test to make sure we don't regress in the future? thanks

[ic3man5]

Could you please add a test to make sure we don't regress in the future? thanks

done

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/misc/stdbuf (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/misc/usage_vs_getopt (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/timeout/timeout (passes in this run but fails in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/timeout/timeout (passes in this run but fails in the 'main' branch)

[cakebaker]

Thanks!