Sync with 2.3.5

* maint:
  Git 2.3.5
  docs: clarify what git-rebase's "-p" / "--preserve-merges" does

Documentation/git-rebase.txt

@@ -362,7 +362,9 @@ default is `--no-fork-point`, otherwise the default is `--fork-point`.
 
 -p::
 --preserve-merges::
-	Instead of ignoring merges, try to recreate them.
+	Recreate merge commits instead of flattening the history by replaying
+	commits a merge commit introduces. Merge conflict resolutions or manual
+	amendments to merge commits are not preserved.
 +
 This uses the `--interactive` machinery internally, but combining it
 with the `--interactive` option explicitly is generally not a good