fmt: fix bug that adds unnecessary module name to generic types (#12758)

vlib/v/ast/types.v

@@ -1054,16 +1054,15 @@ pub fn (t &Table) type_to_str_using_aliases(typ Type, import_aliases map[string]
 		}
 		.generic_inst {
 			info := sym.info as GenericInst
-			res = sym.name.all_before('<')
+			res = t.shorten_user_defined_typenames(sym.name.all_before('<'), import_aliases)
 			res += '<'
 			for i, ctyp in info.concrete_types {
-				res += t.get_type_symbol(ctyp).name
+				res += t.type_to_str_using_aliases(ctyp, import_aliases)
 				if i != info.concrete_types.len - 1 {
 					res += ', '
 				}
 			}
 			res += '>'
-			res = t.shorten_user_defined_typenames(res, import_aliases)
 		}
 		.void {
 			if typ.has_flag(.optional) {

vlib/v/fmt/tests/generics_keep.vv

@@ -1,4 +1,4 @@
-import mymod { ImpNode }
+import mymod { Data, ImpNode }
 
 fn foobar_mymod<U>(inode ImpNode<U>) ImpNode<U> {
 	return ImpNode{}
@@ -14,7 +14,9 @@ fn (_ Foo) simple<T>() T {
 	return T{}
 }
 
-struct GenericStruct<A, B> {}
+struct GenericStruct<A, B> {
+	v Data<Data<A>, B>
+}
 
 fn proper_generics(gs GenericStruct<A, B>) GenericStruct<A, B> {
 	return gs

vlib/v/tests/generics_test.v

@@ -573,7 +573,7 @@ fn test_generic_detection() {
 	})
 
 	// this final case challenges your scanner :-)
-	assert boring_function<TandU<TandU<int,MultiLevel<Empty_>>, map[string][]int>>(TandU<TandU<int,MultiLevel<Empty_>>, map[string][]int>{
+	assert boring_function<TandU<TandU<int, MultiLevel<Empty_>>, map[string][]int>>(TandU<TandU<int,MultiLevel<Empty_>>, map[string][]int>{
 		t: TandU<int,MultiLevel<Empty_>>{
 			t: 20
 			u: MultiLevel<Empty_>{