Documentation Fix for ConfigSlurper
GROOVY-6385: groovy.bat: Can't use question mark in script parameters

As suggested by Dominique on the mailing list:

http://groovy.329449.n5.nabble.com/Can-t-use-question-mark-in-script-parameters-td5716658.html
GROOVY-6401: Method return type inference breaks with inheritance

Conflicts:
	src/test/groovy/transform/stc/ClosuresSTCTest.groovy