Update docs/source/futures.rst

Co-authored-by: Patrick Hoefler <61934744+phofl@users.noreply.github.com>

docs/source/futures.rst

@@ -343,7 +343,7 @@ part of a function:
 Submit task and retrieve results from a different process
 ---------------------------------------------------------
 
-Sometimes a we care about retrieving a result but not necessarily from the same process.
+Sometimes we care about retrieving a result but not necessarily from the same process.
 
 .. code-block:: python