Added help for setting up Stratum mining (#7584)

* Added help for setting up Stratum mining

Signed-off-by: ITStarMan100 <danhopeman@outlook.com>

* removed duplication from help message; fixed spotless

Signed-off-by: Sally MacFarlane <macfarla.github@gmail.com>

---------

Signed-off-by: ITStarMan100 <danhopeman@outlook.com>
Signed-off-by: Sally MacFarlane <macfarla.github@gmail.com>
Co-authored-by: Sally MacFarlane <macfarla.github@gmail.com>

besu/src/main/java/org/hyperledger/besu/RunnerBuilder.java

@@ -805,7 +805,7 @@ public class RunnerBuilder {
     if (miningParameters.isStratumMiningEnabled()) {
       if (!(miningCoordinator instanceof PoWMiningCoordinator powMiningCoordinator)) {
         throw new IllegalArgumentException(
-            "Stratum server requires an PoWMiningCoordinator not "
+            "Stratum mining requires the network option(--network) to be set to CLASSIC. Stratum server requires a PoWMiningCoordinator not "
                 + ((miningCoordinator == null) ? "null" : miningCoordinator.getClass().getName()));
       }
       stratumServer =

besu/src/main/java/org/hyperledger/besu/cli/options/MiningOptions.java

@@ -59,7 +59,10 @@ public class MiningOptions implements CLIOptions<MiningParameters> {
 
   @Option(
       names = {"--miner-stratum-enabled"},
-      description = "Set if node will perform Stratum mining (default: ${DEFAULT-VALUE})")
+      description =
+          "Set if node will perform Stratum mining (default: ${DEFAULT-VALUE})."
+              + " Compatible with Proof of Work (PoW) only."
+              + " Requires the network option (--network) to be set to CLASSIC.")
   private Boolean iStratumMiningEnabled = false;
 
   @Option(