merlin-imenu works nicely with `SPC / i`.
merlin-iedit is a refactoring tool that locates all occurences of an
identifier in scope and you can use multiple cursors to edit.
integration with evil-multiedit could be better.
There is also a merlin-xref backend, but since we got the individual
def/lookup/etc. already bound not sure if it is worth using it.
Signed-off-by: Edwin Török <edwin@etorok.net>