Fix the "Edit on GitHub" link (#11149)
Fix the "Edit on GitHub" link (#11149)

Workaround the issue by replacing surplus `origin/`,
update the template with upstream (https://github.com/readthedocs/sphinx_rtd_theme/blob/master/sphinx_rtd_theme/breadcrumbs.html) which now requires to use `page_source_suffix` instead of `suffix` (which is missing `.rst`)
jupyter/jupyterlab,jupyter/jupyterlab,jupyter/jupyterlab,jupyter/jupyterlab,jupyter/jupyterlab