--file-types output is racy

[scop]

When running --file-types over a directory containing many files, using several threads, some lines are garbled in the output, apparently because multiple threads output simultaneously. Running with --threads=1 avoids the issue.

An example from running in the checked out https://github.com/scop/bash-completion/tree/master/completions dir, on a box with 2 cores (4 "CPUs"). Output varies between runs, but every one exhibits the same issue.

$ typos --file-types | grep -v ':-$'
./Makefile.am:make
./update-rc.d:d
-
-
./invoke-rc.d:d
./checksec:-./chgrp:
-
./btdownloadheadless.py:py
./apt-get:-./apt-cache:
-
./_umount:./_udevadm-
./vipw:./usermod:--

./tracepath:./tree:--

./rpm2tgz:-./secret-tool:
-
-

The following lines are expected, there should be no other output from the above command.

./Makefile.am:make
./update-rc.d:d
./invoke-rc.d:d
./btdownloadheadless.py:py