Deprecations as Data: deprecation detection script

[Tadeusz Sośnierz]

Hello Parrots,
As the next step for Deprecations as Data (which is one of the goals for
the 3.3 release), in the recent commit[1] I added a script which scans
code for deprecations and reports them to the user. The deprecations are
obviously taken from api.yaml, which now needs few more sections so the
deprecations can be identified (as visible in the commit). So far it
detects the :init sub flag and the Complex PMC usage, but it already
gives around 150 lines of output when ran in the Parrot source tree.

Of course it would make sense if most of the deprecations (if possible)
have the regexes added in api.yaml, for what I'd like you to ask. One of
the desired features is to enable using just plain strings instead of
Perl 6 regexes, and that's on my TODO.

Patches, ideas and criticism welcome.

Kind regards,
Ted

[1] https://github.com/parrot/parrot/commit/b8c1df9c