reverseproxy: clarify the reason for skipping an iteration

Author: mohammed90

modules/caddyhttp/reverseproxy/reverseproxy.go

@@ -131,7 +131,8 @@ func (h *Handler) Provision(ctx caddy.Context) error {
 
 	// get validation out of the way
 	for i, v := range h.Upstreams {
-		// the special cases arise with LookupSRV present, so skip the iteration if it's empty.
+		// Having LookupSRV non-empty conflicts with 2 other config parameters: active health checks, and upstream dial address.
+		// Therefore if LookupSRV is empty, then there are no immediately apparent config conflict and the iteration can be skipped.
 		if v.LookupSRV == "" {
 			continue
 		}