kern_reboot(9): some updates

[mhorne]

Summary

• This function no longer disables interrupts
• MLINK to reboot.9
• Document rebooting variable
• The mentions of autoconfiguration is more about shutdown_nice(), coming in the next commit.
• Describe the RB_* flags relevant to this function
• Describe behaviour when shutdown hooks fail the reset
• Describe expected execution contexts
• Add FF copyright
• xref panic(9)
• xref this page in reboot(2)

[markj]

share/man/man9/kern_reboot.9

104

The tense is inconsistent in several of the points below as well.

[mhorne]

Make the verb tense consistent in the list of actions.

[pauamma_gundo.com]

Minor nits, fixable on commit if nothing else stands out.

share/man/man9/kern_reboot.9

49

65

[mhorne]

Handle nits.

[rpokala]

share/man/man9/kern_reboot.9

72

Might want to define what "Halt the system in-place" means.

100

The existing wording -- if a NO flag is not set -- is not very clear. Perhaps something like this instead:

Unless the
.Dv RB_NOSYNC
flag is set in
.Fa howto ,
sync and unmount the system's disks by calling
.Xr vfs_unmountall 9 .

114–117

is not set

128

s/unusual/unlikely/