Revert "doc/knotc: fix a typesetting issue"

This reverts commit d63f136d.

doc/man/knotc.8in

@@ -261,8 +261,7 @@ Unset the item data in the transaction.
 .UNINDENT
 .SS Note
 .sp
-Empty or \fB\-\-\fP (two dashes) \fIzone\fP parameter means all zones or all zones with a
-transaction.
+Empty or \fB\-\-\fP \fIzone\fP parameter means all zones or all zones with a transaction.
 .sp
 Use \fB@\fP \fIowner\fP to denote the zone name.
 .sp

doc/man_knotc.rst

@@ -239,8 +239,7 @@ Actions
 Note
 ....
 
-Empty or ``--`` (two dashes) *zone* parameter means all zones or all zones with a
-transaction.
+Empty or **--** *zone* parameter means all zones or all zones with a transaction.
 
 Use **@** *owner* to denote the zone name.