rights.4: Remove sentence implying that rights are a mask

Capability rights passed to cap_rights_* are (now) not simple bitmaks
and cannot be ORed together in general (although it will work for
certain subsets of rights).

Remove sentence that implied rights are masks. We already have the
sentence "The complete list of capability rights is provided below" so
listing the rights without an introductory sentence seems fine.

PR: 277057