[docs] add viewcode Sphinx extension
@@ -39,7 +39,7 @@ import recommonmark.parser
# Add any Sphinx extension module names here, as strings. They can be
# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
# ones.
-extensions = ["sphinx.ext.autodoc", "sphinx.ext.napoleon"]
+extensions = ["sphinx.ext.autodoc", "sphinx.ext.viewcode", "sphinx.ext.napoleon"]
# Add any paths that contain templates here, relative to this directory.
templates_path = ["_templates"]
