Fix some false negatives for [single_char_pattern]

[nixxquality]

Please write a short comment explaining your change (or "none" for internal only changes)

changelog: Fix some false negatives for [single_char_pattern]

I noticed that clippy wasn't complaining about my usage of split_once("x") in a personal project so I updated the list of functions.

I had to update the test case for an unrelated issue because replace is now included in the list of functions to be linted.

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @camsteffen (or someone else) soon.

Please see the contribution instructions for more information.

[nixxquality]

What's up with these failing tests? I did test before I committed and I re-tested now as well and nothing fails locally.

[llogiq]

It seems like our code doesn't live up to your improved requirements. The dogfood tests shows where updates are needed.

[nixxquality]

How do I run those tests locally?
Following the instructions in basics.md to "only run dogfood tests" using cargo test --test dogfood doesn't produce any failing results.

[camsteffen]

Not sure why cargo test didn't work, but CI is passing now! Changes look good. Please squash commits (or change the commit message to something like "Fix dogfood").

[camsteffen]

Thanks! @bors r+

[bors]

📌 Commit 01e302b has been approved by camsteffen

[bors]

⌛ Testing commit 01e302b with merge a5d5976...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: camsteffen
Pushing a5d5976 to master...