Links to anchors should display the name of the anchor on the screen

Currently, the links to anchors are imported (by CONFLUENCE-17) with no labels, just like this:

[[doc:>>anchor="anchor name"]]

this uses the default link label generator of XWiki, which currently is the title of the document. Thus, all these links will be displayed with the title of the current document as label.
Ideally, they should be displayed with the name of the anchor as label. In order to make this explicit and not rely on the default link label generator, the import should generate

[[anchor name>>doc:||anchor="anchor name"]]