Update matchesCallFilter guidance to recommend tel: codes

Using tel: or mailto: works for repeat callers, and the new documentation recommends against using a contacts content lookup URI, as we don't explicitly look up phone numbers associated with the contact at the time of the matchesCallFilter call.

Bug: 183924362
Bug: 203806689
Bug: 192592755
Test: NotificationManagerTest
Change-Id: I4786f3206f145ab4273a1151a9356101582e9044