inline triple backtick foo.bar in doc comment incorrectly identifies foo as lang, stripping it in docs

[timotheecour]

Example

when true:
  ##[
  a1 ```foo.bar```

  a2
  ```foo
  bar
  ```
  ]##

Current Output

doc comment in nim code:

same code as comment but in rst file:

Expected Output

current output (stripping foo in the 1st foo.bar is incorrect; it looks like it's interpretting foo as the language of a markdown block but that seems incorrect (eg stackoverflow doesn't do that)

the question is whether to treat this case as markdown emulation or rst:

• if treating as markdown emulation, it should render

foo.bar

• if treating as rst, it should render with backticks, using double backticks `` as delimiters:

`foo.bar`

We should do what's best for nim here if there's an ambiguity.
This ties into how to escape single backticks /cc @a-mr refs #17260:

• if we use rst interpretation, this gives a way to render backticks
• if we use markdown interpretation, then to render backticks we'd need to do as follows:

## ``` `foo.bar` ```

(the leading and trailing space are stripped out; it's a markdown feature)

Additional Information

pip3 install rst2html
cat t11956d.rst | rst2html.py > /tmp/z01.html
generates:

1.5.1 2f213db

[timotheecour]

nim-lang/RFCs#355 would fix this (and other issues)