Removed JSON deprecation warnings

[propensive]

Removes the deprecation warnings which were added to JSON objects and classes prior to their removal from the Scala standard library. Now that this project has been branched into a separate module, the deprecation warnings can be removed.

[gourlaysama]

LGTM, thanks! Now I am wondering why only the JSON package got deprecated...

@soc: was there any other reason for this being deprecated, apart from the move (you deprecated it in scala/scala@3e1a075)?

[soc]

Yes, the disastrous performance. You shouldn't be using scala-parser-combinators in the first place, but the toy implementation of JSON was just even more misleading than the existence of parser combinators in the standard library, because users thought it was intended for usage in production.

Basically, the whole split-into-a-module was a way to get rid of it as fast as possible.

Just like for akka-actors, it would be good to write a migration document to move scala-parser-combinator code to parboiled2 and let scala-parser-combinators die.

So the right action is to add @deprecated to the rest of the library, announce that it will go away, and get rid of it for good.

There is no point in keeping scala-parser-combinators alive longer than necessary.

[gourlaysama]

@soc thanks, that makes sense. I never used the JSON implementation...

I agree on the need for a migration guide, I'll look into that (first I need to refresh my understanding of parboiled2).

[soc]

Let's mention @sirthias, so he's aware of what's happening here.

[sirthias]

Thanks for the ping, Simon!
I still think that parser combinators do serve a purpose as a nice example of how Scala enables elegant and concise solutions to everyday problems (like parsing). I do like the parser combinators implementation.
However, it's true that users should be fully aware of its limitations and especially the runtime performance they can (or cannot) expect.

[SethTisue]

Was the decision to un-deprecate discussed somewhere, or only on this ticket?

[SethTisue]

@retronym directed me to https://issues.scala-lang.org/browse/SI-8863 (which links to more extensive discussion at https://groups.google.com/d/msg/scala-user/nT15jFY7CgE/CiXPZeTP5A0J)