Contract 'he is not' to he's not instead of he'sn't

src/2-two/contraction-two/api/contract.js

@@ -45,8 +45,8 @@ const contract = function () {
   // spencer would -> spencer'd
   m = doc.match('#Person would')
   setContraction(m, `'d`)
-  // would not -> wouldn't
-  m = doc.match('(is|was|had|would|should|could|do|does|have|has|can) not')
+  // would not -> wouldn't (skip words already contracted above, like he's)
+  m = doc.match('(is|was|had|would|should|could|do|does|have|has|can) not').ifNo('@hasContraction')
   setContraction(m, `n't`)
   // i have -> i've
   m = doc.match('(i|we|they) have')