Added --ws-refresh-delay option. (#493)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

docs/Reference/Pantheon-CLI-Syntax.md

@@ -504,6 +504,20 @@ The default is 127.0.0.1:8546.
 !!!note
     This option is not used when running Pantheon from the [Docker image](../Getting-Started/Run-Docker-Image.md#exposing-ports). 
 
+### ws-refresh-delay
+
+```bash tab="Syntax"
+--ws-refresh-delay=<refresh delay>
+```
+
+```bash tab="Example"
+--ws-refresh-delay="10000"
+```
+
+Refresh delay for Websocket synchronizing subscription in milliseconds. 
+The default is 5000. 
+
+
 ### help
 
 ```bash tab="Syntax"

docs/Using-Pantheon/RPC-PubSub.md

@@ -58,7 +58,7 @@ Use `eth_subscribe` to create subscriptions for the following event types:
 * [New headers](#new-headers)
 * [Logs](#logs)
 * [Pending transactions](#pending-transactions)
-* [Sychronizng](#synchronizing) 
+* [Synchronizng](#synchronizing) 
 
 ### New Headers
 
@@ -147,7 +147,7 @@ are included in the notifications. Otherwise, the transaction hashes are include
         }
         ```
 
-#### Logs
+### Logs
 
 Use the `logs` parameter with `eth_subscribe` to be notified of logs included in new blocks. You can 
 specify a [filter object](../Reference/JSON-RPC-API-Objects.md#filter-options-object) to receive notifications 
@@ -204,7 +204,7 @@ The logs subscription returns [Log objects](../Reference/JSON-RPC-API-Objects.md
     }
     ```
 
-#### Pending Transactions
+### Pending Transactions
 
 Use the `newPendingTransactions` parameter with `eth_subscribe` to be notified of pending transactions 
 added to the transaction pool for the node. 
@@ -239,11 +239,14 @@ This means the subscription can publish notifications for the same pending trans
     }
     ```
 
-#### Synchronizing
+### Synchronizing
 
 Use the `syncing` parameter with `eth_subscribe` to be notified about synchronization progress.
 
-The sychronizing subscription returns an object indicating the synchronization progress.
+The synchronizing subscription returns an object indicating the synchronization progress. 
+
+Use the [`--ws-refresh-delay` option](../Reference/Pantheon-CLI-Syntax.md#ws-refresh-delay) to configure how 
+often the synchronizing subscription returns an object. The default is 5000 milliseconds. 
 
 !!!example
     To subscribe to synchronizing notifications: