A couple of days ago when verifying the report about being forced to
pay for a second tin when eating one from a stack on a shop's floor,
wishing for 'tins' (rather than 'tins of foo meat') was repeatedly
producing tin wands instead. The name "tin" and the wand description
"tin" in objects[] were being given 50:50 chance for either one by
the 3.6.1 wishing code. Wishing for "tins of spinach" also gave me
a tin wand on the first attempt. Handle 'tin(s)' more explicitly.
This also does some reformatting.