[ngrams] refactor opaque Int into TermsWeight newtype

4 jobs for 224-dev-understanding-ngrams in 47 minutes and 37 seconds (queued for 6 seconds)
Status Job ID Name Coverage
  Cabal
passed #16659
cabal

00:19:42

 
  Stack
passed #16660
stack

00:06:32

 
  Bench
manual #16661
allowed to fail manual
bench
 
  Test
passed #16662
test

00:21:22