Forbid '<', '>', ' ', '\n', '\r' in parser hook names.

Forbid '<', '>', ' ', '\n', '\r' in parser hook names.
Registering a tag hook with < or > on its name resulted in a UNIQ marker.
Spaces, tabs or LF do work (CR fails due to the CR->LF transformation),
but it's easier to also forbid them, just as they are not allowed in other
markup languages.