Add many sysctl descriptions in kern

[kaktus]

sys/kern/kern_exec.c

135

Use style(9) similar to the entry before, the documentation string should be in a separate line, using proper indentation of 4 spaces.

sys/kern/kern_shutdown.c

170

This should be four spaces and doc sting in a new line.

sys/kern/kern_synch.c

98

Here too.

sys/kern/sched_4bsd.c

438

And too.

sys/kern/sched_ule.c

3130

And too.

sys/kern/subr_kobj.c

71

And too :-)

[antranigv_freebsd.am]

Following style(9) guidelines

[jhb]

sys/kern/kern_exec.c

127

Perhaps "Location of process' ps_strings structure"

132

Perhaps "Top of process stack" (usrstack is the top, not the bottom of the stack, and even then we store various things on the stack such as argv[] and environment arrays before the actual stack used by main())

135

Perhaps "Stack memory permissions". This has the same value as the "prot" argument to mmap (bitmask of PROT_* constants), and the description of "prot" in mmap(2) is "permissions"

sys/kern/kern_synch.c

98

Might be nice to say what it is used for? I think it might be the scaling factor used for load average values, but haven't looked to see how userland (e.g. top or ps) uses this.

sys/kern/kern_umtx.c

243

s/Maximal/Maximum/? maybe s/one/each/ as well

[antranigv_freebsd.am]

addressing jhb's comments

[antranigv_freebsd.am]

More description regarding fscale