is_regex_pattern only recognized the BRE-escaped form \| and not a bare |,
so a pattern like "Jornak|Silverlake|Orissa" was treated as one literal
string (including the pipe characters) and silently returned no matches.
This contradicted the tool docstring, which explicitly advertises
"error|warn" as an auto-detected regex example, and misled models into
concluding the searched terms were absent from the file.
Checking for a bare | also covers the escaped form, since \| contains |,
and normalize_regex already converts escaped pipes before compilation.
Literal patterns without regex metacharacters are unaffected.
Fixes#26781
Classic298
504e724fde