Fix: math rendering with sphinx 5.3.0 (#527)

* update source for mathjax, define mathjax as html renderer

* removed sphinx extension imgmath

* removed mathjax source link

doc/conf.py

@@ -33,7 +33,6 @@
     'sphinx.ext.doctest',
     'sphinx.ext.intersphinx',
     'sphinx.ext.todo',
-    'sphinx.ext.imgmath',
     'sphinx.ext.viewcode',
     'sphinx.ext.mathjax',
     'sphinxcontrib.bibtex',
@@ -347,8 +346,8 @@
     'numpy': ('https://numpy.org/doc/stable', None)
 }
 
-# Use more reliable mathjax source
-mathjax_path = 'https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML'
+# The name of math_renderer extension for HTML output.
+html_math_renderer = 'mathjax'
 
 # Remove the copyright notice from docstrings: