PadMessageHandler: Run the `clientReady` hook asynchronously

doc/api/hooks_server-side.md

@@ -851,7 +851,7 @@ The context is the raw message received from the user.
 Example:
 
 ```javascript
-exports.clientReady = (hookName, {padId}) => {
+exports.clientReady = async (hookName, {padId}) => {
   console.log(`Client has joined pad ${padId});
 };
 ```

src/node/handler/PadMessageHandler.js

@@ -832,7 +832,7 @@ const handleClientReady = async (socket, message, authorID) => {
     return;
   }
 
-  hooks.callAll('clientReady', message);
+  await hooks.aCallAll('clientReady', message);
 
   // Get ro/rw id:s
   const padIds = await readOnlyManager.getIds(message.padId);