Extended syntax for forall, exists

[lou1306]

The Java parser and AST classes appear to support

forall x : A . y : B . phi

As a shorthand for

forall x : A . forall y : B . phi

At the moment our grammar does not handle this. Should it? In the end I do not think it saves a lot of space and it slightly complicates the AST structure. Moreover I think using . in two contexts like this might cause issues in Langium. I suggest we either drop this feature, or use , (comma) to separate quantified variables under the same quantifier, like this:

forall x : A , y : B . phi