Consider adding a general `ExecuteAction::with_end_key` method

[cmbrandenburg]

Currently, the ExecuteAction has two methods for setting the “end key”:

• with_end_key_inclusive
• with_end_key_exclusive

Consider generalizing both methods into one method—something like:

fn with_end_key<K>(self, end_key: K, inclusivity: ???) -> Self

The ??? may be a marker type, with one type denoting inclusivity and another denoting exclusivity.

Note another change: the key parameter is a reference, not a value.