Fix typo in Lib/concurrent/futures/thread.py (GH-13953)

(cherry picked from commit 552ace7498722f1add9f3782751b0d365f4c24c8)

Co-authored-by: ubordignon <48903745+ubordignon@users.noreply.github.com>
diff --git a/Lib/concurrent/futures/process.py b/Lib/concurrent/futures/process.py
index dd14eae..2b2b78e 100644
--- a/Lib/concurrent/futures/process.py
+++ b/Lib/concurrent/futures/process.py
@@ -505,7 +505,7 @@
                 worker processes will be created as the machine has processors.
             mp_context: A multiprocessing context to launch the workers. This
                 object should provide SimpleQueue, Queue and Process.
-            initializer: An callable used to initialize worker processes.
+            initializer: A callable used to initialize worker processes.
             initargs: A tuple of arguments to pass to the initializer.
         """
         _check_system_limits()
diff --git a/Lib/concurrent/futures/thread.py b/Lib/concurrent/futures/thread.py
index 2426e94..9e669b2 100644
--- a/Lib/concurrent/futures/thread.py
+++ b/Lib/concurrent/futures/thread.py
@@ -125,7 +125,7 @@
             max_workers: The maximum number of threads that can be used to
                 execute the given calls.
             thread_name_prefix: An optional name prefix to give our threads.
-            initializer: An callable used to initialize worker threads.
+            initializer: A callable used to initialize worker threads.
             initargs: A tuple of arguments to pass to the initializer.
         """
         if max_workers is None: