Update source/Tutorials/Intermediate/Writing-an-Action-Server-Client/…

…Cpp.rst

Co-authored-by: Chris Lalancette <[email protected]>
Signed-off-by: Felipe Gomes de Melo <[email protected]>

source/Tutorials/Intermediate/Writing-an-Action-Server-Client/Cpp.rst

@@ -164,7 +164,7 @@ An action server requires 6 things:
 5. A callback function for handling cancellation: ``handle_cancel``.
 6. A callback function for handling goal accept: ``handle_accept``.
 
-The implementation of the various callbacks is done with [lambda expressions](https://en.cppreference.com/w/cpp/language/lambda) whitin the constructor.
+The implementation of the various callbacks is done with [lambda expressions](https://en.cppreference.com/w/cpp/language/lambda) within the constructor.
 Note that all of the callbacks need to return quickly, otherwise we risk starving the executor.
 
 We start with the callback for handling new goals: