Warn in case of superfluous parentheses

Property definitions

nitc :: simple_misc_analysis $ AExpr :: warn_parentheses
	# Warn in case of superfluous parentheses
	private fun warn_parentheses(v: SimpleMiscVisitor) do end
src/frontend/simple_misc_analysis.nit:106,2--107,58

nitc :: simple_misc_analysis $ AParExpr :: warn_parentheses
	redef fun warn_parentheses(v)
	do
		v.warning(self, "parentheses", "Warning: superfluous parentheses.")
	end
src/frontend/simple_misc_analysis.nit:111,2--114,4