The bug report assumed "you mime throwwing something" feedback
from 't-' was a typo, but 'throwwing' gets generated from 'throw'.
Change ing_suffix() not to double final 'w'. Presumeably 'w' and 'y'
are exceptions because they're sometimes used as vowels.
Change 'strrchr()' to 'rindex()' like the rest of nethack. Someday
those will need to be switched the other way around.
Add some missing bounds checking, although since ing_suffix() isn't
used for user-supplied strings, that's probably superfluous.
6fc21bfaa0