Add the pref to no need to escape all meta character for regexp (not by default).
Update rust syntax files to https://github.com/mozilla/rust/commit/01eb5e8ad39a57e9fc31569983c1b9d5905a7e58
Merge branch 'master' into plugins

* master:
  Update rust syntax files to https://github.com/mozilla/rust/commit/01eb5e8ad39a57e9fc31569983c1b9d5905a7e58
  Add the pref to no need to escape all meta character for regexp (not by default).