skip all type parameters in recordType

We only did this for Container in the type switch, but not for Struct.
The added test case panics otherwise.
Just like in the previous case, we still don't need to recurse
into type parameters for fieldToStruct to be filled correctly.

Fixes #899

testdata/script/typeparams.txtar

@@ -24,7 +24,7 @@ type GenericVector[GenericParamT any] []GenericParamT
 
 type GenericGraph[T any] struct {
 	Content T
-	Edges []GenericGraph[T]
+	Edges   []GenericGraph[T]
 }
 
 type PredeclaredSignedInteger interface {
@@ -40,7 +40,7 @@ type StringableSignedInteger interface {
 type CombineEmbeds interface {
 	string | int
 
-	interface { EmbeddedMethod() }
+	interface{ EmbeddedMethod() }
 	RegularMethod()
 }
 
@@ -49,3 +49,7 @@ type Slice[T any] []T
 func sliceOfPointer() Slice[*any] {
 	return []*any{}
 }
+
+type Map[K, V comparable] map[K]V
+
+var _ = Map[string, struct{}]{}