On Wikidata are performed a lot of item merge actions, and [human] users need a feature to help them check faster and easier performed merges.
It's needed to create a link for the target/source item in each merge edit summary. Currently for the target it looks as follows:

(‎Merged item into Q10000)
(‎Redirected to Q10000)

and should be:

(‎Merged item into [[Q10000]])
(‎Redirected to [[Q10000]])

This provide quick access to new item and helps users very much to check faster such actions in a list of user contributions, item history, watchlist, recent changes and whatever they appear.

In target-item history such a simple link is not very useful, and it should be replaced with direct link to the source-item history:

(‎Merged item from [//www.wikidata.org/w/index.php?title=Q10000&action=history Q10000])

If not built-in in core, this can be implemented as a gadget.