"no_value" indicates that the the attribute is a single word, not a
key=value pair. If the type is BOOLEAN then the attribute is considered
true, if it's a STRING then the key is used instead of a value.

"consumes_rest" indicates that the particular key takes the unparseable
tail of the string for a value.

This allows parsing tc-style strings. Consider this filter:

              ,------ regular key/value pair
       ,-----'----.
  root handle 1234: matchall action simple foo bar baz
    |                  |     `-----------.-----------'
    |                  |                 `- "", STRING, consumes_rest
    |                  `------------------- "kind", STRING, no_value
    `-------------------------------------- "root', BOOLEAN, no_value