Remove trailing whitespace.

Fix terminology issue brought up by Bug Hunting in PR 47314.
The boot records in extended partitions are called "Extended Boot Record"
(EBR); use that in the documentation where appropriate.

branches: 1.18.2;
From Bug Hunting:
- use more common option list header line;
- remove superfluous `.Pp' macro (fixes mandoc(1) warning);
- bump date.

branches: 1.17.6;
Sort option descriptions, per PR 43119 by Bug Hunting.
Refer to -r from -w.
Bump date.

Grammar fix.

Add an option (-s) to specify which sector to read to parse the partition
table. Useful if the disk has remapping drivers installed into it (such as
Ontrack Disk Manager).

Added as an option instead of automatic behavior to let the user scan any
of the two partition tables at will.

xref dkctl(8)

make the description of -w and -r more clear, per PR 13503.

Cross-link fdisk(8), mbr(8), and mbrlabel(8) in the SEE ALSO sections,
as suggested in PR 14288. Also add a little white space to mbr(8) to
make it a little more readable.

fix a typo

Drop unnecessary .Pp.

clarify that -w updates the in-core label if changed, and if -r is
given as well, the on-disk label will then be updated.

change behaviour of flags slightly:
-w write in-core label if changed
-r update on-disk as well as in-core label (with -w)
-f force update (-w), even if there's been no change

-r behaviour suggested by matt green. what used to be `-f' is now `-wrf'

more rewording
- mbrlabel updates the disklabel; it doesn't generate it
- it doesn't just affect the incore label, so remove the `incore' qualifier

i got sick of the brain damage that mbrlabel used to do, and had
gotten bitten by mbrlabel trashing my incore disklabel to a point where
the machine wasn't usable, so I reworked it:

* only update the incore (and on-disk) label if `-f' is given. by default,
the proposed disklabel will be printed but no changes will occur
* add -q, to make the default operation a bit more quiet.
* leave existing `used' in-core partition slots alone, and only add entries
to the incore label if:
- there's not an existing partition of the same size and offset
(even of a different type)
- there's a free partition slot (`unused', with size == 0)
* use DIOCWDINFO instead of DIOCSDINFO, to update the incore as well as
the on-disk label
* use showpartitions() from ../disklabel/printlabel.c

this should make mbrlabel a *lot* more useful.

xref (disklabel.8, fdisk.8, mbrlabel.8) as appropriate

branches: 1.4.4;
Moved from mbrlabel.8,v

More and more .Os cleanups. .Os is defined in the tmac.doc-common file,
so we shouldn't override it with versions in the manpages. Many more to
come.

Shorten name line to fit.
Thanks to Hubert Feyrer (feyrer@rfhs8012.fh-regensburg.de) for pointing this out

Add a utility to allow access to the partitions of a
MBR labeled disk (i.e. a disk partitioned by fdisk)
on any platform (including extended partitions).