Only invoke env.note_dependency() when there is a source file

[oharboe]

No description provided.

[dhellmann]

I'm not sure what note_dependency() does. Can you add some details about why this is a useful change to the commit message?

[oharboe]

I'm not sure what note_dependency() does. Can you add some details about why this is a useful change to the commit message?

This function should only be called with files. It is being invoked with a directory in the case that there's no source file to depend on. This must be unintentional.

Calling it with a folder, causes other sphinx plugins to fail as they see folders as dependencies, which is illegal.

Such as in mgeier/sphinx-last-updated-by-git#27

[dhellmann]

This PR was released in version 0.9.1. https://doughellmann.com/releases/sphinxcontrib-datatemplates-0-9-1/

Thank you!