Ignore mutagen sync temporary files

[nilbus]

Mutagen is a sync tool for remote development that copies files into place on a remote machine [running listen/guard] when edits are made on a local machine. To perform an atomic update, it creates a temp/staging file and moves it into place.

Normally this results in an addition, which results in the change being ignored by many guard plugins. Listen's QueueOptimizer can detect this as an "editor save" when it detects that a silenced temp file is moved to replace a watched file.

This patch updates the ignore pattern to detect mutagen temp files, silencing them and allowing the staging file move to be detected properly as a modification.

Post-merge tasks

• Update Guardfile DSL wiki ignore section to include this new default

[coveralls]

Coverage decreased (-0.04%) to 97.843% when pulling bae2631 on nilbus:mutagen into 896c74c on guard:master.

[nilbus]

Mutagen creates all its files with a .mutagen-temporary prefix (reference). I put the prefix pattern ending in .* in the suffixes where all other tempfile patterns are. Matching will be as performant as the others, but let me know if you think it should go into its own separate ignore prefixes list since it's not technically a suffix.

[benjaminoakes]

Thank you for addressing this

[rymai]

@nilbus Thank you, looks good to me! ❤️ 💛 💚 🚀