fix: Spelling error `a,out` -> `amount` (#596)

diff --git a/google/api_core/retry/retry_streaming_async.py b/google/api_core/retry/retry_streaming_async.py
index ed4edab..2924ba1 100644
--- a/google/api_core/retry/retry_streaming_async.py
+++ b/google/api_core/retry/retry_streaming_async.py

@@ -260,7 +260,7 @@
     Args:
         predicate (Callable[Exception]): A callable that should return ``True``
             if the given exception is retryable.
-        initial (float): The minimum a,out of time to delay in seconds. This
+        initial (float): The minimum amount of time to delay in seconds. This
             must be greater than 0.
         maximum (float): The maximum amount of time to delay in seconds.
         multiplier (float): The multiplier applied to the delay.

diff --git a/google/api_core/retry/retry_unary_async.py b/google/api_core/retry/retry_unary_async.py
index f97ea93..3bdf6c7 100644
--- a/google/api_core/retry/retry_unary_async.py
+++ b/google/api_core/retry/retry_unary_async.py

@@ -185,7 +185,7 @@
     Args:
         predicate (Callable[Exception]): A callable that should return ``True``
             if the given exception is retryable.
-        initial (float): The minimum a,out of time to delay in seconds. This
+        initial (float): The minimum amount of time to delay in seconds. This
             must be greater than 0.
         maximum (float): The maximum amount of time to delay in seconds.
         multiplier (float): The multiplier applied to the delay.