Bump python dependencies to fix CI

CI got broken as the sphinxcontrib.applehelp extension was changed to
require Sphinx version 5.0.0+ in patch bump here:
sphinx-doc/sphinxcontrib-applehelp#15

Dependencies have been bumped to fix this.

This slightly changes some styling, file name styling in code block captions
is a little broken, will need to fix later.

Did not do much in-depth investigation if anything else is broken, but
skimmed through most pages and they look fine.

requirements.txt

@@ -1,7 +1,7 @@
-sphinx==4.3.2
+sphinx==7.2.6
 sphinx-intl==2.0.1
 sphinx-JDLinker==2.0.1
-furo==2021.11.23
-m2r2==0.3.2
-sphinx-design==0.0.13
+furo==2024.01.29
+m2r2==0.3.3.post2
+sphinx-design==0.5.0
 pyyaml==6.0.1