attempt to fix sphinx warnings

docs/requirements-rtd.txt

@@ -1,6 +1,7 @@
 --only-binary PyQt5,numpy
 
 setuptools
+sphinx~=7.4.7
 sphinx-rtd-theme
 PyQt5
 AnyQt

docs/source/conf.py

@@ -46,7 +46,7 @@
 # The suffix(es) of source filenames.
 # You can specify multiple suffix as a list of string:
 # source_suffix = ['.rst', '.md']
-source_suffix = '.rst'
+source_suffix = {'.rst': 'restructuredtext'}
 
 # The encoding of source files.
 #source_encoding = 'utf-8-sig'
@@ -73,7 +73,7 @@
 #
 # This is also used if you do content translation via gettext catalogs.
 # Usually you set "language" from the command line for these cases.
-language = None
+language = "en"
 
 # There are two options for replacing |today|: either, you set today to some
 # non-false value, then it is used:
@@ -296,4 +296,4 @@
 
 
 # Example configuration for intersphinx: refer to the Python standard library.
-intersphinx_mapping = {'https://docs.python.org/': None}
+intersphinx_mapping = {'python': ('https://docs.python.org/3', None)}