words.constant: store true for "constant" word prop
words.constant: store true for "constant" word prop

Fixes ``CONSTANT: foo f``

factor/factor,factor/factor,mrjbq7/factor,mrjbq7/factor,tgunr/factor,tgunr/factor,tgunr/factor,mrjbq7/factor,mrjbq7/factor,mrjbq7/factor,tgunr/factor,factor/factor,tgunr/factor,factor/factor,factor/factor,factor/factor,tgunr/factor,mrjbq7/factor