Add parsing html with transformTemplates to customDatasources documentation

[dklimpel]

Tell us more.

I have a similar use case to the nginx directory listing example and wanted to make it simpler and parse with jsonata.

That is the result:

"customDatasources": {
    "ubuntu_apt": {
      "defaultRegistryUrlTemplate": "https://nginx.org/download",
      "transformTemplates": [
        "{ \"releases\": $.releases.{ \"version\": $match(version, /^nginx-(.+)\\.tar\\.gz$/).groups[0] }[version] }"
      ],
      "format": "html"
    }
  },

I also use it with {{packageName}} like this:

"{ \"releases\": $.releases.{ \"version\": $match(version, /^{{packageName}}-(.+)\\.tar\\.gz$/).groups[0] }[version] }"

I think it would be interesting to include it in the documentation.

It would be really nice if you could also use depName at this point.

[viceice]

• https://docs.renovatebot.com/modules/datasource/custom/#usage
• https://github.com/renovatebot/renovate/blob/main/lib/modules/datasource/custom/readme.md

[dklimpel]

I know the documentation. I would suggest expanding it. If there is interest, I can also open a PR.

[viceice]

feel free to improve 🤗