FieldMask shouldn't convert names with trailing underscore

[AdrienVannson]

When converting a field mask to JSON, path values with a trailing underscore are converted instead of being rejected.

import { create, toJson, fromJson } from "@bufbuild/protobuf";
import { FieldMaskSchema } from "@bufbuild/protobuf/wkt";

var msg = create(FieldMaskSchema, { paths: ["abc_"] });
console.log(msg);

var json = toJson(FieldMaskSchema, msg);  // Should fail but works
console.log(json);

var msg2 = fromJson(FieldMaskSchema, json);  // The underscore is lost
console.log(msg2);

In the same situation, the official Python implementation fails:

from google.protobuf.field_mask_pb2 import FieldMask
from google.protobuf.json_format import MessageToJson

msg = FieldMask(paths=["abc_"])
MessageToJson(msg)  # ValueError: Fail to print FieldMask to Json string: Trailing "_" in path name abc_.

[AdrienVannson]

There is a similar problem with a_1a

[jcready]

protobuf-es/packages/protobuf/src/to-json.ts

Line 491 in 05dab19

if (p.match(/_[0-9]?_/g) || p.match(/[A-Z]/g)) {

Yeah it needs the same fix as timostamm/protobuf-ts#552