man2/*: srcfix: fix warnings from "mandoc -Tlint"

man2/*: srcfix: fix warnings from "mandoc -Tlint"

  Remove superfluous paragraph macros.

  Remove ".br" if it is before a line that starts with a space
character, as such lines automatically cause a break.

###

  The output is unchanged, except two empty lines are added at the
bottom (before the footer line) in the output of "nroff" for the files
"alloc_hugepages.2" and "userfaultfd.2".

###

  Examples of warnings from "mandoc -Tlint":

mandoc: access.2:283:2: WARNING: skipping paragraph macro: PP after SH

mandoc: adjtimex.2:185:2: WARNING: skipping paragraph macro: PP empty

mandoc: futex.2:728:2: WARNING: skipping paragraph macro: IP empty

mandoc: getsid.2:48:2: WARNING: skipping paragraph macro: br before text line with leading blank

mandoc: init_module.2:290:2: WARNING: skipping paragraph macro: PP after SS

mandoc: ioctl_fideduperange.2:27:2: WARNING: skipping paragraph macro: br after SH

Signed-off-by: Bjarni Ingi Gislason <bjarniig@rhi.hi.is>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>