fix multi "generic" type, some docs

docs/clustering.md

@@ -40,6 +40,7 @@ await cluster.close();
 ## Auth with password and username
 
 Specifying the password in the URL or a root node will only affect the connection to that specific node. In case you want to set the password for all the connections being created from a cluster instance, use the `defaults` option.
+
 ```javascript
 createCluster({
   rootNodes: [{

docs/transactions.md

@@ -0,0 +1,29 @@
+# [Transactions](https://redis.io/docs/interact/transactions/) ([`MULTI`](https://redis.io/commands/multi/)/[`EXEC`](https://redis.io/commands/exec/))
+
+Start a [transaction](https://redis.io/docs/interact/transactions/) by calling `.multi()`, then chaining your commands. When you're done, call `.exec()` and you'll get an array back with your results:
+
+```javascript
+const [setReply, getReply] = await client.multi()
+  .set('key', 'value')
+  .get('another-key')
+  .exec();
+```
+
+## `exec<'typed'>()`/`execTyped()`
+
+A transaction invoked with `.exec<'typed'>`/`execTyped()` will return types appropriate to the commands in the transaction:
+
+```javascript
+const multi = client.multi().ping();
+await multi.exec(); // Array<ReplyUnion>
+await multi.exec<'typed'>(); // [string]
+await multi.execTyped(); // [string]
+```
+
+> :warning: this only works when all the commands are invoked in a single "call chain"
+
+## [`WATCH`](https://redis.io/commands/watch/)
+
+You can also [watch](https://redis.io/docs/interact/transactions/#optimistic-locking-using-check-and-set) keys by calling `.watch()`. Your transaction will abort if any of the watched keys change.
+
+The `WATCH` state is stored on the connection (by the server). In case you need to run multiple `WATCH` & `MULTI` in parallel you'll need to use a [pool](./pool.md).