fix thread pool docs to remove blocking

docs/reference/modules/threadpool.asciidoc

@@ -36,16 +36,14 @@ pools, but the important ones include:
 
 Changing a specific thread pool can be done by setting its type and
 specific type parameters, for example, changing the `index` thread pool
-to `blocking` type:
+to have more threads:
 
 [source,js]
 --------------------------------------------------
 threadpool:
     index:
-        type: blocking
-        min: 1
+        type: fixed
         size: 30
-        wait_time: 30s
 --------------------------------------------------
 
 NOTE: you can update threadpool settings live using
@@ -85,10 +83,7 @@ number of cores times 5.
 The `queue_size` allows to control the size of the queue of pending
 requests that have no threads to execute them. By default, it is set to
 `-1` which means its unbounded. When a request comes in and the queue is
-full, the `reject_policy` parameter can control how it will behave. The
-default, `abort`, will simply fail the request. Setting it to `caller`
-will cause the request to execute on an IO thread allowing to throttle
-the execution on the networking layer.
+full, it will abort the request.
 
 [source,js]
 --------------------------------------------------
@@ -97,27 +92,4 @@ threadpool:
         type: fixed
         size: 30
         queue_size: 1000
-        reject_policy: caller
---------------------------------------------------
-
-[float]
-==== `blocking`
-
-The `blocking` pool allows to configure a `min` (defaults to `1`) and
-`size` (defaults to the number of cores times 5) parameters for the
-number of threads.
-
-It also has a backlog queue with a default `queue_size` of `1000`. Once
-the queue is full, it will wait for the provided `wait_time` (defaults
-to `60s`) on the calling IO thread, and fail if it has not been
-executed.
-
-[source,js]
---------------------------------------------------
-threadpool:
-    index:
-        type: blocking
-        min: 1
-        size: 30
-        wait_time: 30s
 --------------------------------------------------