fix #H6285 - speaking vs strangulation

Reading a scroll while blind is permitted if you know its label, but
message is "as you pronounce the words, the scroll vanishes" unless
you are poly'd into a form which can't make sounds, in which case you
"cogitate" rather than "pronouce".  Switch to the cogitate variant if
you are suffering from strangulation.

Casting spells didn't even have the distinction; you could cast them
without regard to speech capability.  Check for that.  Unlike with
scrolls, now you can't cast if you can't speak (or grunt or bark or
whatever) instead of having a variant description of the action, so
this is a bigger change.

doc/fixes36.1

@@ -453,6 +453,10 @@ give feedback when released from a bear trap
 	features entry was split across two lines
 recovery of strength lost due to weakness from hunger was vulnerable to abuse
 monsters hit by scroll of earth boulder did not get angry
+hero could "pronounce the words on the scroll" when blind (if its label is
+	known) even while being strangled at the time
+hero could cast spells while poly'd into a form which can't speak (or grunt,&c)
+	or while being strangled
 
 
 Fixes to Post-3.6.0 Problems that Were Exposed Via git Repository