MFC r364335,r364336,r364337,r364351

r364335 | imp | 2020-08-18 00:07:34 -0600 (Tue, 18 Aug 2020) | 6 lines

Modernize a bit.

Remove PC Card specific information. It's of little value these days and on
the way out after most of its drivers have been removed.
Use iwn instead of wi device.

r364336 | imp | 2020-08-18 00:18:18 -0600 (Tue, 18 Aug 2020) | 9 lines

Document that PC Card will likely be removed before 13.

This was discussed in arch@ a while ago. Most of the 16-bit drivers that it
relied on have been removed. There's only a few other drivers remaining that
support it, and those are very rare the days (even the once ubiquitious wi(1)
is now quite rare).

Indvidual drivers will be handled separately before pccard itself is removed.

r364337 | imp | 2020-08-18 00:34:56 -0600 (Tue, 18 Aug 2020) | 2 lines

Use better gone_in_dev rather than just gone_in to print the device name.

r364351 | imp | 2020-08-18 11:29:01 -0600 (Tue, 18 Aug 2020) | 4 lines

bt(4) has already been removed. Add a deprecation notice.

MFC After: 1 day