Delete empty directories in $SAGE_DOC

[jdemeyer]

In #19127, the automatic deleting of empty directories was removed, because of the mistaken assumption that it was not needed. While it's not needed in all cases, it is needed in one case:

it can happen that git checkout leaves behind an empty directory (since it does not track directories), for example src/doc/en/reference/manifolds. These directories should be deleted, otherwise Sphinx complains.

CC: @hivert @mezzarobba

Component: build

Author: Jeroen Demeyer

Branch/Commit: cabdf45

Reviewer: John Palmieri

Issue created by migration from https://trac.sagemath.org/ticket/20010

[jdemeyer]

Dependencies: #19127

[jdemeyer]

Author: Jeroen Demeyer

[jdemeyer]

Branch: u/jdemeyer/delete_empty_directories_in__sage_doc

[jdemeyer]

New commits:

cabdf45

Delete empty directories in $SAGE_DOC before running Sphinx

[jdemeyer]

Commit: cabdf45

[jdemeyer]

Changed dependencies from #19127 to none

[jhpalmieri]

comment:5

Looks good. With previous versions of docbuilding, there were many empty directories and so I objected to printing out the message Deleting empty directory ... for each one. With this version, we should usually have just a few empty directories, if any, so it's fine to print it.

[jhpalmieri]

Reviewer: John Palmieri

[vbraun]

Changed branch from u/jdemeyer/delete_empty_directories_in__sage_doc to cabdf45