Sugar: Propagate user-given annotations from original expr into Sugar.Expression
GUI is hard-coded to use ExpressionN with ()
Sugar.MStorePoint
Sugar.Definition[U/N] are parameterized on ()
Sugar.makeTypeInfo: Can do annotations
GUI uses ExprGuiM.Payload and SugarExpr
Use SugarExpr/ExprGuiM.Payload instead of rHiddenGuids
Collapsed expressions steal the payloads of the expanded terms.

The collapsed expression will get marked.
Don't assignPrefix self-guid to self
Move maybeToMPlus to Maybe.Utils
Safer removal of wrappers in injectIntoHoles
HoleEdit.Results: injectIntoHoles: Takes payloads as arg
Gui keeps track of which subexprs were injected
Shrink down injected results
Shrink wrapped arg to line height
Oops: Don't always forget the ExpressionGui wrapper/alignment