fn normalize_pattern(p: &str, escape: Option<u8>) -> Cow<'_, [u8]>Expand description
Converts a SQL LIKE pattern to the internal backslash escape convention.
This mirrors PostgreSQL’s do_like_escape: ESCAPE '' disables escaping and
doubles backslashes, ESCAPE '\' leaves the pattern unchanged, and any other
escape character is rewritten to the internal \ escape marker.