Support recommended comments style

[mantasindrasius]

protobuf.js version: 6.8.8

official protobuf Language Guide recommends using C/C++ style for comments, meaning either // or /* ... */.

Example:

/* SearchRequest represents a search query, with pagination options to
 * indicate which results to include in the response. */

message SearchRequest {
  required string query = 1;
  optional int32 page_number = 2;  // Which page number do we want?
  optional int32 result_per_page = 3;  // Number of results to return per page.
}

https://developers.google.com/protocol-buffers/docs/proto3 (see Adding Comments)

However, protobuf.js is now only support triple slash comments ///.

If I use the recommended style, the parsed AST is left with comment: null in case other styles are used.

This makes it very hard to use this great library for code or documentation generation for protos that the developer does not own.

[crdev]

👍

[jeremy-ww]

https://github.com/dcodeIO/protobuf.js/blob/master/src/tokenize.js#L165-L169

[mkosieradzki]

@dcodeIO Any comment on that? Your idea from #640 doesn't work well here (basically it is impossible to write comments that will work correctly with protobuf.js and protoc at the same time)... Maybe a switch between to modes would be a good approach?