Incorrect and missing API documentation (for 2.4) regarding Cache namespace

[farzadghanei]

As I followed the API documentation for Cache name space I found there should be an AbsrtractCache class, but there is no such class in reality; Instead CacheProvider is the abstract parent class for implementations. Also there are far more implementations available (Including VoidCache which I needed and I implemented myself, extending AbstractCache) that are missing from the documentation, like VoidCache, FileSystemCache, RedisCache, RiakCache, etc.

[Ocramius]

That API doc seems totally outdated: we moved cache out of common ages ago...

[beberlei]

Cache is not its own API project because its not listed in projects.yml of the website. We need to fix that for all new components.

[Majkl578]

API docs for Cache are now available here: https://www.doctrine-project.org/api/cache/latest/index.html
It is also documented as a separate component now: https://www.doctrine-project.org/projects/cache.html