Changing the LoadBalancingStrategy type hints to be defined as optional. Fixed wording in pydocs

Author: petyaslavova

redis/asyncio/cluster.py

@@ -124,13 +124,14 @@ class RedisCluster(AbstractRedis, AbstractRedisCluster, AsyncRedisClusterCommand
           https://redis.io/docs/manual/scaling/#redis-cluster-configuration-parameters
     :param read_from_replicas:
         | @deprecated - please use load_balancing_strategy instead
-        | Enable read from replicas in READONLY mode. You can read possibly stale data.
+        | Enable read from replicas in READONLY mode.
           When set to true, read commands will be assigned between the primary and
           its replications in a Round-Robin manner.
+          The data read from replicas is eventually consistent with the data in primary nodes.
     :param load_balancing_strategy:
         | Enable read from replicas in READONLY mode and defines the load balancing
           strategy that will be used for cluster node selection.
-          You can read possibly stale data (when reading from replicas).
+          The data read from replicas is eventually consistent with the data in primary nodes.
     :param reinitialize_steps:
         | Specifies the number of MOVED errors that need to occur before reinitializing
           the whole cluster topology. If a MOVED error occurs and the cluster does not
@@ -236,7 +237,7 @@ def __init__(
         startup_nodes: Optional[List["ClusterNode"]] = None,
         require_full_coverage: bool = True,
         read_from_replicas: bool = False,
-        load_balancing_strategy: Union[LoadBalancingStrategy, None] = None,
+        load_balancing_strategy: Optional[LoadBalancingStrategy] = None,
         reinitialize_steps: int = 5,
         cluster_error_retry_attempts: int = 3,
         connection_error_retry_attempts: int = 3,

redis/cluster.py

@@ -498,7 +498,7 @@ def __init__(
         require_full_coverage: bool = False,
         reinitialize_steps: int = 5,
         read_from_replicas: bool = False,
-        load_balancing_strategy: Union["LoadBalancingStrategy", None] = None,
+        load_balancing_strategy: Optional["LoadBalancingStrategy"] = None,
         dynamic_startup_nodes: bool = True,
         url: Optional[str] = None,
         address_remap: Optional[Callable[[Tuple[str, int]], Tuple[str, int]]] = None,
@@ -535,7 +535,7 @@ def __init__(
         :param load_balancing_strategy:
              Enable read from replicas in READONLY mode and defines the load balancing
              strategy that will be used for cluster node selection.
-             You can read possibly stale data (when reading from replicas).
+             The data read from replicas is eventually consistent with the data in primary nodes.
         :param dynamic_startup_nodes:
              Set the RedisCluster's startup nodes to all of the discovered nodes.
              If true (default value), the cluster's discovered nodes will be used to