fix: always pass declaration to resolve_decl_into_nominal

fixes #888

spec/lang/subtyping/typealias_spec.lua

@@ -43,4 +43,14 @@ describe("typealias", function()
       local type Test = {StringFoo: StringBar}
       local test: Test = {}
    ]]))
+
+   it("nested generic type aliases work with early resolution (regression test for #888)", util.check([[
+      local record Generic<T>
+         x: T
+      end
+
+      local record Export
+         type Test = Generic<string>
+      end
+   ]]))
 end)

tl.tl

@@ -8159,7 +8159,7 @@ do
          -- otherwise, this can't be an alias.
 
          -- resolve the nominal into a structural type
-         local struc = resolve_decl_into_nominal(self, nom, found)
+         local struc = resolve_decl_into_nominal(self, nom, found or nom.found)
 
          -- wrap it into a new non-alias typedecl
          local td = a_type(ta, "typedecl", { def = struc } as TypeDeclType)