MFC r332317, r332439, r332442

Approved by: re

r332317:
[man] Fix return type of BUS_ADD_CHILD(9)

Fix return type of BUS_ADD_CHILD(9) in SYNOPSYS section,
it should be device_t, not int

PR: 207389

r332439:
Fix quotes in the example code in syslog(3) BUGS section

mdoc treats verbatim quotes in .Dl as a string delimiter and does
not pass them to the rendered output. Use special char \*q to specify
double quote

PR: 216755

r332442:
Bump .Dd value (forgot to do this in r332439)