Minor rlib cleanups
Robert Sprowson authored
dbox.c: address of cancelled by dereference
event.c: spelling
txtar.c: don't grab the caret when clicking toggle size
txtedit.c: use BOOL for a boolean
win.c: when looking at the behind window handle we want -1 not 'DUD' (which happens to be -1)
wimp.h: add comment about window handle -3
Retagged as RISC_OSLib-5_83.

Version 5.83. Not tagged
dc7ea073