Doc: reference the "stash list" in autostash docs

In documentation pertaining to autostash behavior, we refer to the
"stash reflog". This description is too low-level as the reflog refers
to an implementation detail of how the stash works and, for end-users,
they do not need to be aware of this at all.

Change references of "stash reflog" to "stash list", which should
provide more accessible terminology for end-users.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-merge.txt

@@ -106,12 +106,12 @@ commit or stash your changes before running 'git merge'.
 `MERGE_HEAD` is present unless `MERGE_AUTOSTASH` is also present in
 which case 'git merge --abort' applies the stash entry to the worktree
 whereas 'git reset --merge' will save the stashed changes in the stash
-reflog.
+list.
 
 --quit::
 	Forget about the current merge in progress. Leave the index
 	and the working tree as-is. If `MERGE_AUTOSTASH` is present, the
-	stash entry will be saved to the stash reflog.
+	stash entry will be saved to the stash list.
 
 --continue::
 	After a 'git merge' stops due to conflicts you can conclude the

Documentation/git-rebase.txt

@@ -257,7 +257,7 @@ See also INCOMPATIBLE OPTIONS below.
 	Abort the rebase operation but HEAD is not reset back to the
 	original branch. The index and working tree are also left
 	unchanged as a result. If a temporary stash entry was created
-	using --autostash, it will be saved to the stash reflog.
+	using --autostash, it will be saved to the stash list.
 
 --apply:
 	Use applying strategies to rebase (calling `git-am`