Move decorators, transform-class-properties from stage-1 to stage-2 p…

…reset docs (#883)

* Swap decorators from stage-1 to stage-2 preset docs

See: babel/babel#3613

TL; DR:
> TC39 advanced decorators to stage 2, w/ crucial open questions re:
> function, param, & property decorators needing good answers for
> progress.
- @BrendanEich

* Move transform-class-properties link to stage-2

* Re-add message about transform-decorators-plugin being disabled

docs/plugins/preset-stage-1.md

@@ -9,8 +9,6 @@ package: babel-preset-stage-1
 This preset includes the following plugins:
 
 - [transform-class-constructor-call](/docs/plugins/transform-class-constructor-call) (Deprecated)
-- [transform-class-properties](/docs/plugins/transform-class-properties)
-- <del>[transform-decorators](/docs/plugins/transform-decorators)</del> – *disabled pending proposal update*
 - [transform-export-extensions](/docs/plugins/transform-export-extensions)
 
 And all plugins from presets:

docs/plugins/preset-stage-2.md

@@ -9,6 +9,8 @@ package: babel-preset-stage-2
 This preset includes the following plugins:
 
 - [transform-object-rest-spread](/docs/plugins/transform-object-rest-spread)
+- <del>[transform-decorators](/docs/plugins/transform-decorators)</del> – *disabled pending proposal update*
+- [transform-class-properties](/docs/plugins/transform-class-properties)
 
 And all plugins from presets: