Ignore unmatched exclusions in detailed_match_files

[Larry-Labs]

detailed_match_files() raises KeyError when an exclusion matches a file that no previous inclusion added, or when an exclusion is repeated. Remove entries only when present, preserving existing inclusion order and both all_matches modes. Related: #105.

Reproduction on current master:

from pathspec.patterns.gitignore.basic import GitIgnoreBasicPattern
from pathspec.util import detailed_match_files

patterns = list(map(GitIgnoreBasicPattern, ['*.txt', '!*.log']))
result = detailed_match_files(patterns, ['notes.txt', 'debug.log'])
# Previously: KeyError: 'debug.log'; now result contains only 'notes.txt'.

Regression tests cover unmatched exclusions, repeated exclusions, re-inclusion, and removal of an existing match. The unmatched/repeated cases fail on unchanged master. Full unittest discovery passes with the simple and RE2 backends; Hyperscan and the Windows-only case remain untested locally.

Prepared with OpenAI Codex (GPT-6) assistance; the reproduction, tests, and diff were checked before submission.

[cpburnz]

Thanks for finding and fixing this. detailed_match_files() has been neglected.