fix sphinx_prompt config (#349)

Author: zingale

docs/source/conf.py

@@ -46,7 +46,7 @@
     'sphinx.ext.graphviz',
     'sphinx_copybutton',
     'sphinx_math_dollar',
-    'sphinx-prompt',
+    'sphinx_prompt',
     'sphinx_mdinclude',
     'IPython.sphinxext.ipython_console_highlighting',
     'sphinx.ext.githubpages']