Fix WebPubSub README config key name (Azure#25508)

sdk/webpubsub/Microsoft.Azure.WebJobs.Extensions.WebPubSub/README.md

@@ -30,13 +30,13 @@ You can find the **Keys** for you Azure Web PubSub service in the [Azure Portal]
 
 The `AzureWebJobsStorage` connection string is used to preserve the processing checkpoint information as required refer to [Storage considerations](https://docs.microsoft.com/azure/azure-functions/storage-considerations#storage-account-requirements)
 
-For the local development use the `local.settings.json` file to store the connection string, `<connection_name>` can be set to `WebPubSubConnectionString` as default supported in the extension, or you can set customized names by mapping it with `Connection = <connection_name>` in function binding attributes:
+For the local development use the `local.settings.json` file to store the connection string, `<connection-string>` can be set to `WebPubSubConnectionString` as default supported in the extension, or you can set customized names by mapping it with `Connection = <connection-string>` in function binding attributes:
 
 ```json
 {
   "Values": {
     "AzureWebJobsStorage": "UseDevelopmentStorage=true",
-    "<connection_name>": "Endpoint=https://<webpubsub-name>.webpubsub.azure.com;AccessKey=<access-key>;Version=1.0;"
+    "<connection-string>": "Endpoint=https://<webpubsub-name>.webpubsub.azure.com;AccessKey=<access-key>;Version=1.0;"
   }
 }
 ```