fix type checking WAT examples

[rvolosatovs]

While studying the explainer and working on #336 , I found out that the example type checking WAT is not valid. I've quickly tested this by modifying a test case in Wasmtime with the following WAT (it appears that inverted alias form as defined in https://github.com/WebAssembly/component-model/blob/1a3e3cfe68e1ecc0567059cd218296af2e34e977/design/mvp/Explainer.md?plain=1#L390-L397 is not supported by whatever is parsing WAT in Wasmtime)

(component $A
    (type $ListString1 (list string))
    (type $ListListString1 (list $ListString1))
    (type $ListListString2 (list $ListString1))
    (component $B
      (type $ListString3 (list string))
      (type $ListListString3 (list $ListString3))
      (alias outer $A $ListString (type $ListString4))
      (type $ListListString4 (list $ListString4))
      (alias outer $A $ListString2 (type $ListListString5))
    )
)

Which failed with:

Error: unknown type: failed to find name `$ListString`
     --> <anon>:10:39
      |
   10 |                       (alias outer $A $ListString (type $ListString4))

as expected

Proposed version:

(component $A
  (type $ListString1 (list string))
  (type $ListListString1 (list $ListString1))
  (type $ListListString2 (list $ListString1))
  (component $B
    (type $ListString2 (list string))
    (type $ListListString3 (list $ListString2))
    (alias outer $A $ListString1 (type $ListString3))
    (type $ListListString4 (list $ListString3))
    (alias outer $A $ListListString2 (type $ListListString5))
  )
)

[lukewagner]

Oops, I'm sorry, I missed the notification for this PR a while back. Thanks!