Merge branch 'jc/whitespace-incomplete-line' into next

Merge branch 'jc/whitespace-incomplete-line' into next

It does not make much sense to apply the "incomplete-line"
whitespace rule to symbolic links, whose contents almost always
lack the final newline.  "git apply" and "git diff" are now taught
to exclude them for a change to symbolic links.

* jc/whitespace-incomplete-line:
  whitespace: symbolic links usually lack LF at the end