Prepare for Sphinx upgrade

[jdemeyer]

This branch collects a few commits which were originally on #18497 but which are general fixes which make sense even with the current Sphinx.

CC: @hivert

Component: documentation

Author: André Apitzsch, Jeroen Demeyer

Branch/Commit: 3c4e4b0

Reviewer: Frédéric Chapoton

Issue created by migration from https://trac.sagemath.org/ticket/20488

[jdemeyer]

Branch: u/jdemeyer/ticket/20488

[jdemeyer]

Commit: 0a2da2a

[jdemeyer]

New commits:

9d5e4fd	fix warning "more than one target found for cross-reference u'groebner_basis'"
72241c3	Don't use code-block:: python if it's not Python
fbf5406	Trivial autodoc changes
0a2da2a	Fix citation warnings in the first docbuild pass

[sagetrac-git]

Changed commit from 0a2da2a to 3c4e4b0

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

3c4e4b0

Do not doctest SandpileConfig.fire_vertex?

[fchapoton]

comment:6

Looks good but why do you add that

+from six import PY2, iterkeys, iteritems, itervalues, text_type, class_types, \
+    string_types, StringIO

?

[jdemeyer]

comment:7

Replying to @fchapoton:

Looks good but why do you add that

+from six import PY2, iterkeys, iteritems, itervalues, text_type, class_types, \
+    string_types, StringIO

?

That's a line from upstream's autodoc.py.

[fchapoton]

Reviewer: Frédéric Chapoton

[fchapoton]

comment:8

ok, then

[vbraun]

Changed branch from u/jdemeyer/ticket/20488 to 3c4e4b0