TASK: Add ConvertUris note and fix backslashes for LinkEditor type

[koehlerannkathrin]

This PR improves the LinkEditor documentation by clarifying that values
must be converted using @process.convertUris = Neos.Neos:ConvertUris
when rendered in Fusion.

It also removes unnecessary escaped backslashes from the
Neos\Neos\Domain\Link\Link property type notation.

[dlubitz]

Thank you @koehlerannkathrin for this PR.

AFAIS the double slashes are needed here for the rendering of the docs and do not appear in the rendered version.

See: https://neos.readthedocs.io/en/stable/References/PropertyEditorReference.html#property-type-image-neos-media-domain-model-imageinterface-imageeditor-image-selection-upload-editor

Also it would be great if you PR would target Neos 8.3 as it's our lowest maintained branch at the moment.

[mhsdesign]

Thanks for improving the docs;) The backslashes indeed are fine already and rendered correctly ^^

Now to your documentation to use ConvertUris, this change would be correct to target 9.1 as this feature did not exist beforehand...

but id say using ConvertUris here is merely a hacky workaround. Because while we have the uri at hand we choose to render it first into the markup and then go over the markup again and parse it via xml dom parser to adjust the uris.

Instead a helper should be called explicitly ... the think is we might not have such ready to use eel helper at hand ... no one liner at least. Thus i would propose to add Neos.Link.resolveInternalUri() and use this as follows

<a href={Neos.Link.resolveInternalUri(linkObject.href, node, request)} />

That is explict and does everything we need it to.