[single_char_pattern] add strip_prefix and strip_suffix
Title says it all. Adjusted ui tests.
I added the second commit in case you don't like that I moved that table into `single_char_pattern.rs` directly. I don't see any reason why it shouldn't be in that file. It isn't used anywhere else.
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: add strip_prefix and strip_suffix to single_char_pattern lint
5e3160ca0b