commit-graph: suppress warning about using a stale stack addresses

The code is a bit too hard to reason about for CodeQL to figure out
whether the `fill_commit_graph_info()`  function is at all called after
`write_commit_graph()` returns (and hence whether `topo_levels` goes out
of context before it is used again).

The Git project insists that this is correct (and does not want to make
the code more obviously correct), so let's silence CodeQL's complaints
in this instance.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

commit-graph.c

@@ -2561,6 +2561,7 @@ int write_commit_graph(struct odb_source *source,
 
 	g = prepare_commit_graph(ctx.r);
 	for (struct commit_graph *chain = g; chain; chain = chain->base_graph)
+		/* Intentional: codeql[cpp/stack-address-escape] */
 		g->topo_levels = &topo_levels;
 
 	if (flags & COMMIT_GRAPH_WRITE_BLOOM_FILTERS)