Currently when adding external links we have to manually type the syntax. There is an Insert link button but this only enables internal links. Otherwise there is no button (like there is for things like bold, italic etc).
(The following issue makes typing the syntax extra annoying: https://github.com/Requarks/wiki/issues/2062)
Maybe we can extend the Insert link dialog to enable external links?
Maybe also enable keyboard shortcuts like ctrl+k, which is used in the visual editor but also in Github's issues editor.