fmt: fix removal of Abc in import mod { Abc }, where Abc is used in a x is Abc expression (#10286)

vlib/v/fmt/fmt.v

@@ -2429,6 +2429,7 @@ pub fn (mut f Fmt) string_inter_literal(node ast.StringInterLiteral) {
 }
 
 pub fn (mut f Fmt) type_expr(node ast.TypeNode) {
+	f.mark_types_import_as_used(node.typ)
 	f.write(f.table.type_to_str_using_aliases(node.typ, f.mod2alias))
 }
 

vlib/v/fmt/tests/import_selective_expected.vv

@@ -11,6 +11,7 @@ import mod {
 	InterfaceField,
 	InterfaceMethodArg,
 	InterfaceMethodRet,
+	RightOfIs,
 	StructEmbed,
 	StructField,
 	StructMethodArg,
@@ -34,6 +35,9 @@ interface Interface {
 }
 
 fn f(v FnArg) FnRet {
+	if v is RightOfIs {
+	}
+
 	return {}
 }
 

vlib/v/fmt/tests/import_selective_input.vv

@@ -19,6 +19,8 @@ import mod {
 
 	FnArg,
 	FnRet,
+
+	RightOfIs,
 }
 
 struct Struct {
@@ -37,6 +39,8 @@ interface Interface {
 }
 
 fn f(v FnArg) FnRet {
+	if v is RightOfIs {}
+
 	return {}
 }