Workaround the fact that "b" is now a separate command object from...

Workaround the fact that "b" is now a separate command object from "_regexp-break", and thus "help b" doesn't show the possible syntaxes

It would be nice to have a longer-term plan for how to handle help for regular expression commands, since their syntax is highly irregular. I can see a few options (*), but for now this is a reasonable stop-gag measure for the most blatant regression.

(*) the simplest is, of course, to detect a regex command and inherit the syntax for any aliases thereof; it would be nice if this also didn't show the underlying regex command name when the alias is used

llvm-svn: 263523