git-svn: multiple fetch/branches/tags keys are supported
"git svn" can be configured to use multiple fetch, branches, and tags
refspecs by passing multiple --branches or --tags options at init time
or editing the configuration file later, which can be handy when
working with messy Subversion repositories. Add a note to the
configuration section documenting how this works.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Eric Wong <normalperson@yhbt.net>