undocumented 'merge' output letters

[Phil Edwards]

(Because this regards an omission to both the "help" output and the
red-bean book, I've put both lists on the To: line, so caveat lector.)

One of my subversion 1.4 users has come to me saying that he can't
find documentation of some of the status column letters printed during
a merge operation.  I knew what (for example) "G"/"U" meant, but only
because I had once looked at /trunk/subversion/svn/status.c for an
explanation back when I first started using subversion myself.  :-)
So I started looking around, and found that:

- "svn help merge" describes no status letters at all

- "svn help status" only describes letters printed during a stat
operation, not any other op.

- the previous two items also apply to the "complete reference"
chapter of the book (as of r2627), q.v.,
http://svnbook.red-bean.com/nightly/en/svn.ref.svn.c.status.html and
http://svnbook.red-bean.com/nightly/en/svn.ref.svn.c.merge.html

- there doesn't seem to be a comprehensive list on the tigris.org
site, but I could be totally overlooking something there.

Anyhow, just FYI.  Thanks for such a great tool and a great book.