Broken relative external link to the same folder

[ThibautBorn]

When creating a new external Link object , referring to another item in the same object, these are not always correctly resolved.
The problem seems to be that when a relative link is created (eg. a link with relative link 'foo'). The path is added to the plone root.

eg. a link with relative link 'foo' with path on https://classic.demo.plone.org/en/demo/a-folder/test-link

will reroute the user to https://classic.demo.plone.orgfoo/ instead of https://classic.demo.plone.org/en/demo/a-folder/foo

[yurj]

./foo works

https://classic.demo.plone.org/en/demo/a-link -> insert ./foo as external link.