prost-build: do not escape brackets followed by parenthesis in comments

[pgimalac]

A proposal to fix #850.

Allows linking to items in doc comments by not escaping brackets followed by parenthesis.

• Before (brackets always escaped):
  // Some comment with a [Link] -> /// Some comment with a \[Link\]
// Some comment with a [Link](Link) -> /// Some comment with a \[Link\](Link)
• After (brackets not escaped if followed by parenthesis):
  // Some comment with a [Link] -> /// Some comment with a \[Link\]
// Some comment with a [Link](Link) -> /// Some comment with a [Link](Link)

EDIT: I also implemented the case with brackets following brackets [Link][Link] since it appears in some of the tests.
EDIT: I also implemented not escaping brackets which are already escaped, it happens when using the cleanup-markdown feature, or if the user manually escapes brackets.

[pgimalac]

I'm seeing some weird behaviors on the bootstrap test, it looks like the input is escaped twice sometimes (there are times where the brackets in the input of sanitize_line is already escaped)... I'll look into it when I have more time.

[pgimalac]

Some lines are escaped both by ast::get_lines (which reads some file using pulldown_cmark_to_cmark) and then by sanitize_input, resulting in the double escaping I mentioned before.

Note that it's already the case, for example here where the regex only matched the outer brackets.

It seems like the cleanup-markdown feature (which is enabled for the tests) already escapes brackets.

I'll update the regex to avoid double escaping, since anyway if the user escapes the brackets then we don't want to do it again.

[pgimalac]

The diff of prost-types/src/protobuf.rs is really nice:

• removes double escaping (eg. line 1259)
• escapes brackets which weren't escaped before (eg. line 1987)
• do not escape brackets which are a link (eg. line 2288)

[baxterjo]

Hoping to bump this thread. Would be nice to have intra-doc linking in rustdocs.

[LucioFranco]

@pgimalac if you want to get the conflicts resolved we can get this merged.

[pgimalac]

@LucioFranco I fixed the conflicts but there is a build error (unrelated to this PR) in the CI
EDIT: opened #899 to fix that.