WPCS 3.0: Remove the deprecated Sniff::has_whitelist_comment() method

[jrfnl]

PR #1580 for WPCS 2.0.0 deprecated the WPCS native whitelist comments and the associated Sniff::has_whitelist_comment() method.

In WPCS 3.0.0 this method and all calls to it should be removed.

Note: all unit tests testing that the WPCS native whitelist comments are being respected should also be removed at that time. Or alternatively, they can remain and it should be verified that the WPCS native whitelist comment makes no difference anymore.

[kkmuffme]

Is there any possibility of this getting released? Since the has_whitelist_comment function is quite slow

[jrfnl]

@kkmuffme It will be released as part of WPCS 3.0.0.

[kkmuffme]

It's been multiple years since this PR was merged, which is why I asked :-)

[jrfnl]

I am fully aware (though it's actually not been multiple years yet).