Fix various typos in comments, log messages and documentation.

fix various typos in documentation, comments and sysctl device description.
mainly aion -> ation and inlude -> include.

Improvements to the problib(3) API:

==> Provide a much more complete set of setters and getters for different
value types in the prop_array_util(3) and prop_dictionary_util(3)
functions.

==> Overhaul the prop_data(3), prop_number(3), and prop_string(3) APIs
to be easier to use and less awkwardly named, Deprecate the old
awkward names, and produce link-time warnings when they are referenced.

==> Deprecate mutable prop_data(3) and prop_string(3) objects. The old
APIs that support them still exist, but will now produce link-time
warnings when used.

==> When the new prop_string(3) API is used, strings are internally
de-duplicated as a memory footprint optimization.

==> Provide a rich set of bounds-checked gettter functions in and a
corresponding set of convenience setters in the prop_number(3) API.

==> Add a new prop_bool_value(3) function that is equivalent to
prop_bool_true(3), but aligned with the new "value" routines in
prop_data(3), prop_string(3), and prop_number(3).

branches: 1.10.12;
Use .Fn to refer a function name instead of Nm.
Also, use Xr to refer problib(3) in the HISTORY section instead of Nm.

While parsing the man pages, any .Nm occurrence gets replaced by the
value specified in the NAME section. Referencing individual function
names with .Nm was causing makemandb(8) to replicate the complete
NAME section for every such occurrence. This was leading to an
ugly looking snippet in apropos(1)'s output when searched for
any of these man pages.

branches: 1.9.2; 1.9.4;
Punctuation nits.
(adding space makes sure they are not marked up)

Add prop_array_add_cstring{,_no_copy} utility functions as suggested in
PR lib/46723 using the patch provided. (Header file updates are mine.)

Add missing Nd.

Fix a typo and a punctuation nit.

Add a new libquota library, which contains some blocks to build and/or
parse quota plists; as well as a getfsquota() function to retrieve quotas
for a single id from a single filesystem (whatever filesystem this is:
a local quota-enabled fs or NFS). This is build on functions getufsquota()
(for local filesystems with UFS-like quotas) and getnfsquota();
which are also available to userland programs.
move functions from quota2_subr.c to libquota or libprop as appropriate,
and ajust in-tree quota tools.
move some declarations from kernel headers to either sys/quota.h or
quota/quota.h as appropriate. ufs/ufs/quota.h still installed because
it's needed by other installed ufs headers.
ufs/ufs/quota1.h still installed as a quick&dirty way to get a code
using the old quotactl() to compile (just include ufs/ufs/quota1.h instead of
ufs/ufs/quota.h - old code won't compile without this change and this is
on purpose).
Discussed on tech-kern@ and tech-net@ (long thread, but not much about
libquota itself ...)

Remove trailing whitespace.

Add prop_array_add_int* and prop_array_add_uint* functions. These functions
can be used to append specified type to the end of prop_array_t.

Ok'ed by @joerg.

branches: 1.2.2; 1.2.4;
Sort SEE ALSO.

Add prop_array_util functions to proplib. This code is copied/changed
prop_dictionary_util.

From manual page

The prop_array_util family of functions are provided to make getting and
setting values in arrays more convenient in some applications.

OK by mjf@ and freza@.