Fix wrong units in two ExplainPropertyFloat calls.

This is only a latent bug, since these calls are only reached for
non-text output formats, and currently none of those will print
the units.  Still, we should get it right in case that ever changes.

Justin Pryzby

Discussion: https://postgr.es/m/20210415163846.GA3315@telsasoft.com

src/backend/commands/explain.c

@@ -1631,9 +1631,9 @@ ExplainNode(PlanState *planstate, List *ancestors,
 		{
 			if (es->timing)
 			{
-				ExplainPropertyFloat("Actual Startup Time", "s", startup_ms,
+				ExplainPropertyFloat("Actual Startup Time", "ms", startup_ms,
 									 3, es);
-				ExplainPropertyFloat("Actual Total Time", "s", total_ms,
+				ExplainPropertyFloat("Actual Total Time", "ms", total_ms,
 									 3, es);
 			}
 			ExplainPropertyFloat("Actual Rows", NULL, rows, 0, es);