classifier: rm comments: lies waiting to happen
classifier: shorten constant pathing; rm memoization

1.  Remove the `@classification` field, just
recalculate.  It's not heavy duty lifting
2.  Simplify the constant pathing.  We need fewer
constants to get a unique match, let's save some
line width

ALSO:m rm stray comment
rm calls to set_as_defective

There was some weird action-at-a-distance going on
with the setting of the classifcation on the verb.
Now classifications are set *once* by the
classifier.

**THE ONLY EXCEPTION** is for irregular,
present-only verbs.  These are a huge, glaring
exception in the language.

Here, the classifier does as expected and returns
that it is an Irregular verb (true) and
consequently the mutator for Irregular is chosen
(correctly).  As part of the `mutate!` function,
the present-only-and-irregular verb has its
classification overridden to be PresentOnly.  The
`PresentOnlyIrregularMask` bears the responsbility
of performing that mutation.
rm stray byebug; tweak error formatting