Remove incorrect file path from how-to doc index.

drvinceknight · drvinceknight · commit 5766046d00a4 · 2021-10-26T16:39:16.000+01:00
diff --git a/docs/how-to/index.rst b/docs/how-to/index.rst
@@ -28,6 +28,5 @@ with the Axelrod library.
    set_a_seed.rst
    set_player_information.rst
    check_player_equality.rst
-   heterogeneous_matches.rst
    cite_the_library.rst
    contributing/index.rst
