DOC: activate m2r for sphinx/markdown integration

Author: pavoljuhas

doc/manual/source/conf.py

@@ -35,13 +35,16 @@
     'sphinx.ext.autodoc',
     'sphinx.ext.napoleon',
     'sphinx.ext.intersphinx',
+    'm2r',
 ]
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']
 
-# The suffix of source filenames.
-source_suffix = '.rst'
+# The suffix(es) of source filenames.
+# You can specify multiple suffix as a list of string:
+#
+source_suffix = ['.rst', '.md']
 
 # The encoding of source files.
 # source_encoding = 'utf-8-sig'