dnsx/resolver: do not skip blocks or proxies for Plus

Initially, Plus was meant as an anti-censorship transport but shipped as
a "smart" transport instead with tunable abilities (choose among encrypted
resolvers at random, or choose the fastest, or choose the most stable etc)
And so, it now makes sense to not reserve special bypasses (proxy/blocklist).

Author: ignoramous

intra/dnsx/transport.go

@@ -1266,14 +1266,17 @@ func isAnyDefault(ids ...string) bool {
 func overrideProxyIfNeeded(pid string, ids ...string) string {
 	for _, id := range ids {
 		switch id {
-		// note: Goos is anyway hard-coded to use NetExitProxy
+		// notes:
+		// 1. Goos is anyway hard-coded to use NetExitProxy.
+		// 2. Plus simply delegates queries to underlying servers,
+		// which may or may not use proxies.
 		case Goos, Local: // exit
 			return NetExitProxy
 		case CT + Goos, CT + Local: // exit
 			return NetExitProxy
-		case Bootstrap, Default, Plus, System, Preset: // base
+		case Bootstrap, Default, System, Preset: // base
 			return NetBaseProxy
-		case CT + Bootstrap, CT + Default, CT + Plus, CT + System, CT + Preset: // base
+		case CT + Bootstrap, CT + Default, CT + System, CT + Preset: // base
 			return NetBaseProxy
 		}
 	}
@@ -1285,10 +1288,10 @@ func skipBlock(tr ...Transport) bool {
 		if t == nil {
 			continue
 		}
-		switch t.ID().V() {
-		case Default, Plus, BlockFree, Alg, Bootstrap:
+		switch t.ID().V() { // Plus/CT+Plus to skip blocks conditionally?
+		case Default, BlockFree, Alg, Bootstrap:
 			return true
-		case CT + Default, CT + Plus, CT + BlockFree, CT + Alg, CT + Bootstrap:
+		case CT + Default, CT + BlockFree, CT + Alg, CT + Bootstrap:
 			return true
 		}
 	}