criu --help: fix --inherit-fd description

* Simplify phrases, removing duplicate words -- saving 1 line
* Drop <>, use UPPERCASE for variable parts as in other places
* Obey 80 columns

Was:
  --inherit-fd fd[<num>]:<existing>
                        Inherit file descriptors. This allows to treat file desc
riptor
                        <num> as being already opened via <existing> one and ins
tead of
                        trying to open we inherit it:
                            tty[rdev:dev]
                            pipe[inode]
                            socket[inode]
                            file[mnt_id:inode]

Now:
  --inherit-fd fd[NUM]:RES
                        Inherit file descriptors, treating fd NUM as being
                        already opened via an existing RES, which can be:
                            tty[rdev:dev]
                            pipe[inode]
                            socket[inode]
                            file[mnt_id:inode]
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/crtools.c

@@ -883,10 +883,9 @@ usage:
 "                            dev[maj:min]:VAL\n"
 "                        Formats of RES on restore:\n"
 "                            dev[VAL]:DEVPATH\n"
-"  --inherit-fd fd[<num>]:<existing>\n"
-"                        Inherit file descriptors. This allows to treat file descriptor\n"
-"                        <num> as being already opened via <existing> one and instead of\n"
-"                        trying to open we inherit it:\n"
+"  --inherit-fd fd[NUM]:RES\n"
+"                        Inherit file descriptors, treating fd NUM as being\n"
+"                        already opened via an existing RES, which can be:\n"
 "                            tty[rdev:dev]\n"
 "                            pipe[inode]\n"
 "                            socket[inode]\n"