Use package cl-lib instead of deprecated package cl

[logicdavid]

I couldn't get mizar mode to run on Emacs 28, and I think it is because the package cl has been moved to cl-lib and its functions acquire the prefix "cl-" (third becomes cl-third, and incf becomes cl-incf). So I updated mizar.el to use the new package and new functions. Now it run on Emacs 28 and presumably, any Emacs since 24.3, when cl-lib was introduced.

[pqnelson]

There are a few functions you missed upgrading (e.g., line 971 (mizar-pp-parsed-fla (fourth fla)))) should replace fourth with cl-fourth; also instances of sixth should be cl-sixth, etc.).

But the reason Mizar-mode probably won't work on Emacs 28 is because get-line was completely rewritten and broke Mizar-mode.