Bug in env.warn call in intersphinx
I want to link to the repoze.workflow documentation and the '.' is causing the intersphinx extension to emit a warning.
Line 161 in sphinx.ext.intersphinx is apssing an incorrect number or args to warn causing the attached traceback.
A simple fix is attached too. It works, but I'm not sure what the first arg to warn is supposed to communicate, so I've just hardcoded the string 'intersphinx' - there is probably a better way to do it.