git-log.txt: rewrite note on why "--" may be required
In its current form, the note talks about separating options from
"branch names" and "refnames" in the same sentence. This is entirely
inaccurate, as <revision range> need not be a set of branch names or
ref names. Rewrite it to use the word "revision range", to be
consistent with the SYNOPSIS.
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>