git-svn: clarify the referent of dcommit's optional argument
git-svn: clarify the referent of dcommit's optional argument

The documentation of the dcommit subcommand is reworded to clarify that
the optional argument refers to a git branch, not an SVN branch.

The discussion of the optional argument is put into its own paragraph
as is the guidance about using 'dcommit' in preference to 'set-tree'.

The section on REBASE vs. PULL/MERGE is reworded to incorporate the
advice to prefer 'git rebase' previously in the description of 'dcommit'.

Signed-off-by: Jon Seymour <13015cd9b4bd75fb137ba1a80810e07fcd27c10e@gmail.com>
Acked-by: Eric Wong <8c2951295f8292b0c03727bc4652981172298eae@yhbt.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git