Parse text to entities with commonmark

[rnons]

Matrix use commonmark as well. See matrix-org/matrix-js-sdk#1425

Somehow this PR doesn't handle this correctly

on Element

on Texts

The message text contains

`[209876d2](https://github.com/tulir/mautrix-imessage/commit/209876d27c513034adea9cc1475be68327cbbd7e)`

Note the link is wrapped inside a backtick, which is not supported by commonmark and Element as well. Can try on https://spec.commonmark.org/dingus/?text=%60%5B209876d2%5D(https%3A%2F%2Fgit.luolix.top%2Ftulir%2Fmautrix-imessage%2Fcommit%2F209876d27c513034adea9cc1475be68327cbbd7e)%60%0A%0A

[linear]

PLT-272 Matrix: map all messages

unrecognized:

{
  "type": "m.room.message",
  "sender": "@github:maunium.net",
  "content": {
    "body": "**[[tulir/mautrix-wsproxy](https://github.com/tulir/mautrix-wsproxy)]** [Yumekui](https://github.com/Yumekui) opened [pull request #1](https://github.com/tulir/mautrix-wsproxy/pull/1): Make binary statically linked instead of dynamically\n \n> Hey,I'm not really experienced with golang, so take that pull request with a grain of salt.I noticed that the docker image didn't work and searched for a solution. The problem appears to be that the binary isn't statically linked and since you use 'FROM scratch' as a base for the image, the required libraries aren't there.After googling a bit, I found this [site](https://www.arp242.net/static-go.html), which recommended to set CGO_ENABLED=0.After building the image locally myself with that, the image seems to work.",
    "format": "org.matrix.custom.html",
    "formatted_body": "<strong>[<a data-mautrix-no-link href=\"https://github.com/tulir/mautrix-wsproxy\">tulir/mautrix-wsproxy</a>]</strong> <a data-mautrix-no-link href=\"https://github.com/Yumekui\">Yumekui</a> opened <a href=\"https://github.com/tulir/mautrix-wsproxy/pull/1\">\n pull request\n #1</a>: Make binary statically linked instead of dynamically<br/>\n <blockquote><p>Hey,\nI'm not really experienced with golang, so take that pull request with a grain of salt.\nI noticed that the docker image didn't work and searched for a solution. The problem appears to be that the binary isn't statically linked and since you use 'FROM scratch' as a base for the image, the required libraries aren't there.\nAfter googling a bit, I found this <a href=\"https://www.arp242.net/static-go.html\">site</a>, which recommended to set CGO_ENABLED=0.\nAfter building the image locally myself with that, the image seems to work.</p>\n</blockquote>",
    "msgtype": "m.notice",
    "xyz.maubot.github.webhook": {
      "delivery_ids": [
        "f3fee820-6ee4-11eb-9f77-19ce04df810c"
      ],
      "event_type": "pull_request"
    }
  },
  "event_id": "$kGu32p6aHuMdqxkEPUBsbqZbdC1OwLspfoWPcL9_iBM",
  "origin_server_ts": 1613321520758,
  "unsigned": {
    "age": 17248294
  },
  "room_id": "!mautrix-imessage-v6:maunium.net"
}