Re: [PATCH v4 7/7] docs: mention --refetch fetch option

"Robert Coup via GitGitGadget" [off-list ref] writes:

 remote.<name>.partialclonefilter::
-	The filter that will be applied when fetching from this
-	promisor remote.
+	The filter that will be applied when fetching from this	promisor remote.
+	Changing or clearing this value will only affect fetches for new commits.
+	To fetch associated objects for commits already present in the local object
+	database, use the `--refetch` option of linkgit:git-fetch[1].

Good advice to add.

Will replace.  I think we've seen this topic enough times and it
looked reasonably well done.  Let's mark it for 'next' unless we
hear objections soonish.