Reverting changes to AnyVals generated classes in 9a82fc0

 - Since the generator was not changed, the classes no longer represent the generated versions
SI-6898 Document AnyVal box and unbox implemention by BoxesRunTime

  - Added @boxRunTimeDoc@ and @unboxRunTimeDoc@ tokens to AnyVals
  - Doc comments refer to BoxesRunTime.java in the Scala repo
  - No comment for Unit
Merge pull request #2284 from demobox/add-box-unbox-doc-comment

SI-6898 Document AnyVal box and unbox implemention by BoxesRunTime