Update Doc/c-api/intro.rst

Co-authored-by: Terry Jan Reedy <[email protected]>

Author: vstinner

Doc/c-api/intro.rst

@@ -866,7 +866,7 @@ approaches to creating C and C++ extensions for Python:
 * `SWIG <https://www.swig.org>`_
 
 It is recommended to use these abstractions, rather than using directly the
-Python C API. These abstractions are built on top of the C API and handles API
+Python C API. These abstractions are built on top of the C API and handle API
 differences between the different Python versions.
 
 These projects are not supported by the same people who maintain Python, and