core: report pattern file source in regex errors

[bugprone]

Fixes #478.

Summary

When a regex parse error comes from a pattern loaded via -f, ripgrep now prefixes the original regex error with the pattern source path and line number.

The normal path still uses the existing build_many matcher construction. On compile failure, ripgrep checks individual patterns only to identify whether the failing pattern came from -f.

Example

Given two pattern files:

# patterns1
foo

# patterns2
bar
bar(wat
quux

Running:

$ rg -f patterns1 -f patterns2 haystack

Previously reported the error against the alternation built from all patterns:

rg: regex parse error:
    (?:foo)|(?:bar)|(?:bar(wat)|(?:quux)
                    ^
error: unclosed group

Now the error points back to the pattern file and line:

rg: patterns2:2: regex parse error:
    (?:bar(wat)
    ^
error: unclosed group

PCRE2 keeps its own error text with the same patterns2:2: source prefix.

Notes

• -f - is reported as <stdin>:line.
• -e and positional patterns keep the existing fallback error behavior.
• This preserves the regex error details that were lost in Implement custom error for grep errors #590.

Tests

$ cargo fmt --all -- --check
$ git diff --check origin/master..HEAD
$ cargo test -p ripgrep --test integration
$ cargo test -p ripgrep --test integration --features pcre2
$ cargo test --workspace --features pcre2