improve readability, fix code formatting issues

mistletoe/contrib/mathjax.py

@@ -18,11 +18,11 @@ def __init__(self, **kwargs):
 
     def render_math(self, token):
         """
-        Convert single dollar sign enclosed math environments to the \( \) syntax, to support
-        default mathjax settings which ignore single dollar signs for compatibility. 
-        https://docs.mathjax.org/en/latest/basic/mathematics.html#tex-and-latex-input
+        Convert single dollar sign enclosed math expressions to the ``\(...\)`` syntax, to support
+        the default MathJax settings which ignore single dollar signs as described at
+        https://docs.mathjax.org/en/latest/basic/mathematics.html#tex-and-latex-input.
         """
-        if token.content.startswith('$$'): 
+        if token.content.startswith('$$'):
             return self.render_raw_text(token)
         return '\\({}\\)'.format(self.render_raw_text(token).strip('$'))
 

test/test_contrib/test_mathjax.py

@@ -15,9 +15,9 @@ def test_render_html(self):
 
     def test_render_math(self):
         with MathJaxRenderer() as renderer:
-            raw = ['# heading 1\n', '$$\sum\limits_{i=1}^{\infty} \frac{1}{i^p}$$\n', 'with $  x_3 2^{x}  $\n']
+            raw = ['math displayed as a block:\n', '$$ \\sum_{i=1}^{\\infty} \\frac{1}{i^p} $$\n', 'math displayed in-line: $ 2^x $\n']
             token = Document(raw)
             output = renderer.render(token)
-            target = '<h1>heading 1</h1>\n<p>$$\sum\limits_{i=1}^{\infty} \frac{1}{i^p}$$\nwith \(  x_3 2^{x}  \)</p>\n'
+            target = '<p>math displayed as a block:\n$$ \\sum_{i=1}^{\\infty} \\frac{1}{i^p} $$\nmath displayed in-line: \\( 2^x \\)</p>\n'
             target += self.mathjax_src
             self.assertEqual(output, target)