New root_doc variable is ignored.

[jhmeinke]

With version 4.0 sphinx renamed master_doc to root_doc, but this is ignored by sphinxcontrib-bibtex.
If I use root_doc I get the following error message because index.rst does not exist.

extension error (sphinxcontrib.bibtex.domain):
Handler <function env_updated at 0x7f8b63b5f910> for event 'env-updated' threw an exception (exception: 'index')

If I replace root_doc with master_doc everything works fine.

Sphinx v4.4.0
sphinxcontrib-bibtex 2.4.1
Arch Linux

[mcmtroffaes]

Thanks for reporting! This should now be fixed in develop; the fix will be included with the next release.

[jhmeinke]

Thank you! That was amazingly fast!