Cantok

A small update with no changes in functionality.

- The links in the documentation have been corrected.
- A new section dedicated to the ecosystem has been added to the documentation. The first representative of the ecosystem mentioned there is [suby](https://github.com/pomponchik/suby).

Nothing important, just updating the documentation.

A small update, functionality is not affected.

- Added some details to the documentation.
- Added new tests.

A small update with no significant changes in functionality.

- Changed the message with which the `ConditionCancellationError` exception is raised.
- The exception documentation is slightly expanded.

A small but important update.

- Added caching of a positive condition check result for `ConditionToken`.

A small but important stabilization update.

- Added some new tests.
- Fixed an error that occurs when asynchronously waiting for a token if there are no strong references to the result returned by the `wait()` method.
- Added some tooling for mutation testing.
- Deleted some dead code.
- Fixed documentation.