this "name" we use should also be used in the commit message
Branch name must NOT be used (I can not emphasize more strongly here) in commit message - it's redundant, duplicate information, which require additional actions for extracting from log message for processing
Branch-name in Mercurial is permanent meta-data, always stored in each changeset.
If you use Mercurial for "tracking", then the most of usable commands (I can imagine only hg log
for now) are templateable, and you can output branch name easy. If you use some external tool, you can on preparing data for it from Mercurial combine "clean" commit-message and branch-name of changesets
Don't forget about MYOB principle