MFC r340455, r340525, r341598

r340455:
fcntl.2: document an additional error condition

r340525:
mount_fusefs.8: expand HISTORY section

Note that fuse was available from ports long before joining the base system.
Also, update the upstream URL.

r341598:
stat(2): clarify which syscalls modify file timestamps

The list of syscalls that modify st_atim, st_mtim, and st_ctim was quite out
of date and probably not accurate to begin with. Update it, and make it
clear that the list is open-ended.

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D18410