Merge pull request matplotlib#22550 from anntzer/sp3

Author: timhoffm

doc/api/next_api_changes/development/22550-AL.rst

@@ -0,0 +1,2 @@
+sphinx>=3.0 and numpydoc>=1.0 are now required for building the docs
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

doc/conf.py

@@ -19,7 +19,6 @@
 import warnings
 
 import matplotlib
-import sphinx
 
 from datetime import datetime
 import time
@@ -49,10 +48,6 @@
 # usage in the gallery.
 warnings.filterwarnings('error', append=True)
 
-# Strip backslashes in function's signature
-# To be removed when numpydoc > 0.9.x
-strip_signature_backslash = True
-
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = [
@@ -144,9 +139,7 @@ def _check_dependencies():
 warnings.filterwarnings('ignore', category=DeprecationWarning,
                         module='sphinx.util.inspect')
 
-# missing-references names matches sphinx>=3 behavior, so we can't be nitpicky
-# for older sphinxes.
-nitpicky = sphinx.version_info >= (3,)
+nitpicky = True
 # change this to True to update the allowed failures
 missing_references_write_json = False
 missing_references_warn_unused_ignores = False
@@ -429,7 +422,7 @@ def matplotlib_reduced_latex_scraper(block, block_vars, gallery_conf,
 # Sphinx 2.0 adopts GNU FreeFont by default, but it does not have all
 # the Unicode codepoints needed for the section about Mathtext
 # "Writing mathematical expressions"
-fontpkg = r"""
+latex_elements['fontpkg'] = r"""
 \IfFontExistsTF{XITS}{
  \setmainfont{XITS}
 }{
@@ -469,12 +462,7 @@ def matplotlib_reduced_latex_scraper(block, block_vars, gallery_conf,
   Extension      = .otf,
 ]}
 """
-latex_elements['fontpkg'] = fontpkg
 
-# Sphinx <1.8.0 or >=2.0.0 does this by default, but the 1.8.x series
-# did not for latex_engine = 'xelatex' (as it used Latin Modern font).
-# We need this for code-blocks as FreeMono has wide glyphs.
-latex_elements['fvset'] = r'\fvset{fontsize=\small}'
 # Fix fancyhdr complaining about \headheight being too small
 latex_elements['passoptionstopackages'] = r"""
     \PassOptionsToPackage{headheight=14pt}{geometry}

requirements/doc/doc-requirements.txt

@@ -7,11 +7,11 @@
 # Install the documentation requirements with:
 #     pip install -r requirements/doc/doc-requirements.txt
 #
-sphinx>=1.8.1,!=2.0.0
+sphinx>=3.0.0
 colorspacious
 ipython
 ipywidgets
-numpydoc>=0.8
+numpydoc>=1.0
 packaging>=20
 pydata-sphinx-theme>=0.8.0
 mpl-sphinx-theme