Fix(mark doc)/relative image pathing

[chappelo]

Changes

closes #10546

• While using markdoc custom image node if a relative url is passed as src, the image wasn't rendered on webpage. This was fixed by repathing the relative.

Testing

• I tested this by modifying examples/blog to override markdoc’s default image node and then test relative paths, public and http links.

• Different src paths all render correctly on webpage:

![test](./test.png)
![test](../test.jpg)
![test](/test.jpg)
![test](../../../test.jpg)
![test](https://imageIfound.jpg)

Docs

• this fix is already reflected the current docs and removes the need for a work around Relative image syntax does not work with Markdoc custom image node  #10546 (comment)
• https://docs.astro.build/en/guides/integrations-guide/markdoc/#override-markdocs-default-image-node

[changeset-bot]

🦋 Changeset detected

Latest commit: dc105b8

The changes in this PR will be included in the next version bump.

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR