Adds WEBBED dex penalty

Fixes #7452.
Fix GOURMAND

As described in #7445, halves the penalty and minor alteration to
description.  Shouldn't disturb the translators.
Fix FEATHERS

Pretty minor boost, as requested.  Fixes #7446.
Added checking of broken unicode sybols
More diagnostic messages
Mandible-consistency

OK, now no more wearing regular mouthgear over mandibles.
Merge remote-tracking branches 'dda/pr/7456' and 'dda/pr/7460' into dda-master

* dda/pr/7456:
  Mandible-consistency
  Fix FEATHERS
  Fix GOURMAND
  Adds WEBBED dex penalty

* dda/pr/7460:
  More diagnostic messages
  Added checking of broken unicode sybols