Merge branch 'js/fetch-multi-lockfix'

Fetching from multiple remotes into the same repository in parallel
had a bad interaction with the recent change to (optionally) update
the commit-graph after a fetch job finishes, as these parallel
fetches compete with each other.  Which has been corrected.

* js/fetch-multi-lockfix:
  fetch: avoid locking issues between fetch.jobs/fetch.writeCommitGraph
  fetch: add the command-line option `--write-commit-graph`

Documentation/fetch-options.txt

@@ -92,6 +92,10 @@ ifndef::git-pull[]
 	Run `git gc --auto` at the end to perform garbage collection
 	if needed. This is enabled by default.
 
+--[no-]write-commit-graph::
+	Write a commit-graph after fetching. This overrides the config
+	setting `fetch.writeCommitGraph`.
+
 -p::
 --prune::
 	Before fetching, remove any remote-tracking references that no