Add parser.xslt as a prerequisite for parsing

Although this file will generally be generated as a part of the
make·file restart loop, it is possible to wind up with an early error
during dependency generation if files cannot be parsed prior to
resolving make·file dependencies. Depend on it in this case as well,
with the understanding that this will update the types yet again.

If `parser.xslt` _is_ generated as a part of dependency generation
(and, presumably, `.update-types` does not exist) then the dependency
update message should be suppressed, since the other make·file build
script will also be present and active.