message-parser: markdown link parsing is wrong

[paviad]

Description

Markdown parsing of links is wrong.

Steps to reproduce

This markdown source: [Title 1] bla bla [Title 2](https://foo.com/title2) should conver to the following html:

<p>[Title 1] bla bla <a href="https://foo.com/title2">Title 2</a>

But is actually converted to:

<p> <a href="https://foo.com/title2">Title 1] bla bla [Title 2</a>

This is the test that (if added to packages/message-parser/tests/link.test.ts) would fail:

  [
    '[Title 1] bla bla [Title 2](https://foo.com/title2)',
    [paragraph([
      plain('[Title 1] bla bla '),
      link('https://foo.com/title2',[plain('Title 2')])
    ])]
  ]

And this would be the failure diff:

      Array [
        Object {
          "type": "PARAGRAPH",
          "value": Array [
            Object {
    -         "type": "PLAIN_TEXT",
    -         "value": "[Title 1] bla bla ",
    -       },
    -       Object {
              "type": "LINK",
              "value": Object {
                "label": Array [
                  Object {
                    "type": "PLAIN_TEXT",
    -               "value": "Title 2",
    +               "value": "Title 1] bla bla [Title 2",
                  },
                ],
                "src": Object {
                  "type": "PLAIN_TEXT",
                  "value": "https://foo.com/title2",

Insert an image/gif

[paviad]

There are many other things this grammar based parsing gets wrong...

[paviad]

git bisect yields this commit 19690db as the first bad commit

[paviad]

It turns out that in an attempt to accommodate these cases:

• the [Jira [Task] parentheses not working](rocket.chat)
• [Jira [Task] parentheses not working](rocket.chat)

this commit broke the other case