cgen: fix printing struct having fields of arrays of anonymous structs (#16953)

Author: yuyi98

vlib/v/checker/tests/comptime_dump_fields_var_test.out

@@ -2,7 +2,7 @@
 [vlib/v/checker/tests/comptime_dump_fields_var_test.vv:13] val.$field.name: d
 [vlib/v/checker/tests/comptime_dump_fields_var_test.vv:13] val.$field.name: 1
 [vlib/v/checker/tests/comptime_dump_fields_var_test.vv:13] val.$field.name: 0
-[vlib/v/checker/tests/comptime_dump_fields_var_test.vv:13] val.$field.name: _VAnonStruct1{
+[vlib/v/checker/tests/comptime_dump_fields_var_test.vv:13] val.$field.name: struct {
     i: 100
 }
-ok
+ok

vlib/v/gen/c/auto_str_methods.v

@@ -829,7 +829,7 @@ fn (mut g Gen) gen_str_for_struct(info ast.Struct, styp string, typ_str string,
 		g.auto_fn_definitions << fn_builder.str()
 	}
 	fn_builder.writeln('static string indent_${str_fn_name}(${styp} it, int indent_count) {')
-	clean_struct_v_type_name := util.strip_main_name(typ_str)
+	clean_struct_v_type_name := if info.is_anon { 'struct ' } else { util.strip_main_name(typ_str) }
 	// generate ident / indent length = 4 spaces
 	if info.fields.len == 0 {
 		fn_builder.writeln('\treturn _SLIT("${clean_struct_v_type_name}{}");')

vlib/v/slow_tests/inout/printing_struct_with_arrays_of_anon_struct_field.out

@@ -0,0 +1,5 @@
+Abc{
+    a: [struct {
+        b: 'this is b'
+    }]
+}

vlib/v/slow_tests/inout/printing_struct_with_arrays_of_anon_struct_field.vv

@@ -0,0 +1,13 @@
+struct Abc {
+	a []struct {
+		b string
+	}
+}
+
+fn main() {
+	abc := Abc{
+		a: [struct {'this is b'}]
+	}
+
+	println(abc)
+}