(#16412) add `show_diffs` param to file type

When false, this will suppress diffs of the affected files.
Make filetype tests succeed even when local uid == 9000

My UID on my development system is 9000, which was making these tests
fail, because 9000 is used as the fake UID as well.
(#14728) Handle removed files in the PMT changes command.

This patch ensures that "puppet module changes" command reports removed files
as changed rather than exiting with a "file not found" error message when it
encounters a file that should exist according to the metadata.json but which
is not present.
The patch also adds unit & acceptance tests for the "puppet module changes"
command.
correct docs regarding interaction of show_diff config/param
test all permutations of show_diff config/param
Merge branch 'pull-1560'

This closes GH-1560
Merge pull request #1576 from djmitche/fix-filetype-tests

Make filetype tests succeed even when local uid == 9000
Merge pull request #1350 from mruzicka/ticket/master/14728-PMT-changes-handle-removed-files

(#14728) Handle removed files in the PMT changes command.
Simple fix for broken indirection docs

Currently generating the indirection docs fails because of the
resource/validator terminus, for which the autoloader returns nil.
Rather than quietly failing the whole docs build on this error, just
fail the docs for that particular terminus.
Merge branch 'pull-1575'