fmt: remove additional line breaks after call_expr before params struct args (#19795)

Author: ttytm

vlib/v/fmt/fmt.v

@@ -1976,11 +1976,12 @@ fn (mut f Fmt) write_generic_call_if_require(node ast.CallExpr) {
 }
 
 pub fn (mut f Fmt) call_args(args []ast.CallArg) {
-	f.single_line_fields = true
+	old_single_line_fields_state := f.single_line_fields
 	old_short_arg_state := f.use_short_fn_args
+	f.single_line_fields = true
 	f.use_short_fn_args = false
 	defer {
-		f.single_line_fields = false
+		f.single_line_fields = old_single_line_fields_state
 		f.use_short_fn_args = old_short_arg_state
 	}
 	for i, arg in args {

vlib/v/fmt/tests/fn_call_with_call_expr_and_params_struct_args_keep.vv

@@ -0,0 +1,10 @@
+[params]
+struct Bar {
+	bar bool
+}
+
+fn foo(msg string, opts Bar) {
+	println(msg)
+}
+
+foo(123.str(), bar: true)