upgrade to mathjax v3 (always loads latest available 3.x.x version)

Author: dgcampea

rednotebook/util/markup.py

@@ -108,26 +108,15 @@
 
 # MathJax
 FORMULAS_SUPPORTED = True
-MATHJAX_FILE = "https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js"
+MATHJAX_FILE = "https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-svg.js"
 
 # Explicitly setting inlineMath: [ ['\\(','\\)'] ] doesn't work.
 # Using defaults:
 #       displayMath: [ ['$$','$$'], ['\[','\]'] ]
 #       inlineMath:  [['\(','\)']]
 MATHJAX_DELIMITERS = ["$$", "\\(", "\\)", r"\\[", "\\]"]
 MATHJAX = """\
-<script type="text/x-mathjax-config">
-  MathJax.Hub.Config({{
-    messageStyle: "none",
-    config: ["MMLorHTML.js"],
-    jax: ["input/TeX","input/MathML","output/HTML-CSS","output/NativeMML"],
-    tex2jax: {{}},
-    extensions: ["tex2jax.js","mml2jax.js","MathMenu.js","MathZoom.js"],
-    TeX: {{
-      extensions: ["AMSmath.js","AMSsymbols.js","noErrors.js","noUndefined.js"]
-    }}
-  }});
-</script>
+<!--MathJax included-->
 <script type="text/javascript" src="{MATHJAX_FILE}"></script>
 """.format(
     **locals()

tests/test_markup.py

@@ -234,7 +234,7 @@ def test_day_fragment_anchor_element(self, process):
 
     def test_mathjax(self, process):
         document = process("$$x^3$$")
-        assert r'<script type="text/x-mathjax-config">' in document
+        assert r'<!--MathJax included-->' in document
 
 
 class TestGetTexExportConfig: