Change the option name to no-kill-backend.

For consistency with other slimilar option such as no-order,
no-analyze.

doc/pg_repack.rst

@@ -127,7 +127,7 @@ Options:
   -i, --index=INDEX         move only the specified index
   -x, --only-indexes        move only indexes of the specified table
   -T, --wait-timeout=SECS   timeout to cancel other backends on conflict
-  -D, --dont-kill-backend   do not kill other backends when timed out
+  -D, --no-kill-backend     don't kill other backends when timed out
   -Z, --no-analyze          don't analyze at end
 
 Connection options:
@@ -202,13 +202,13 @@ Reorg Options
     pg_repack needs to take an exclusive lock at the end of the
     reorganization.  This setting controls how many seconds pg_repack will
     wait to acquire this lock. If the lock cannot be taken after this duration
-    and ``--dont-kill-backend`` option is not specified, pg_repack will forcibly
+    and ``--no-kill-backend`` option is not specified, pg_repack will forcibly
     cancel the conflicting queries. If you are using PostgreSQL version 8.4
     or newer, pg_repack will fall back to using pg_terminate_backend() to
     disconnect any remaining backends after twice this timeout has passed.
     The default is 60 seconds.
 
-``-D``, ``--dont-kill-backend``
+``-D``, ``--no-kill-backend``
     Skip to repack table if the lock cannot be taken for duration specified
     ``--wait-timeout``, instead of cancelling conflicting queries. The default
     is false.