DOC: change branch name from py3doc-enh-theme to py3doc-enhanced-theme

Author: mgeier

doc/usage.ipynb

@@ -298,8 +298,8 @@
     "  [usage](https://github.com/spatialaudio/nbsphinx/compare/cloud-theme^...cloud-theme)\n",
     "\n",
     "* [sphinx_py3doc_enhanced_theme](https://github.com/ionelmc/sphinx-py3doc-enhanced-theme):\n",
-    "  [example](http://nbsphinx.readthedocs.io/en/py3doc-enh-theme/),\n",
-    "  [usage](https://github.com/spatialaudio/nbsphinx/compare/py3doc-enh-theme^...py3doc-enh-theme)\n",
+    "  [example](http://nbsphinx.readthedocs.io/en/py3doc-enhanced-theme/),\n",
+    "  [usage](https://github.com/spatialaudio/nbsphinx/compare/py3doc-enhanced-theme^...py3doc-enhanced-theme)\n",
     "\n",
     "* [basicstrap](http://pythonhosted.org/sphinxjp.themes.basicstrap/):\n",
     "  [example](http://nbsphinx.readthedocs.io/en/basicstrap-theme/),\n",