================================================================================
MakeShortVerb and DeleteShortVerb
================================================================================
|foo|
+foo+
\MakeShortVerb{\|}
|bar|
\MakeShortVerb*{\+}
+bar+
\DeleteShortVerb{\|}
|quux|
+quux+
--------------------------------------------------------------------------------
(document
  (text)
  (MakeShortVerb (cs) (group (l) (cs) (r)))
  (short_verb (verb_delim) (verbatim) (verb_delim))
  (MakeShortVerb (cs) (star) (group (l) (cs) (r)))
  (short_verb (verb_delim) (verbatim) (verb_delim))
  (DeleteShortVerb (cs) (group (l) (cs) (r)))
  (text)
  (short_verb (verb_delim) (verbatim) (verb_delim)))