[PATCH 0 of 1] edits to "help revisions"

[Stuart W Marks]

(N.B. This patch is against the crew repo, as it seems to contain a
bunch of line wrapping changes in the help text that haven't yet made
it into the mainline.)

This patch updates the "help revisions" text to mention the use of
branch names. This has been discussed a couple times on the list. I
changed the description of negative integers from "topological" to
"sequential" because "topological" implies that this follows the chain
of parents, which is not the case. I also removed the comment about
the non-usefulness of negative integers, as it didn't seem
appropriate.

s'marks