I have come to realize that the pleasant style (argument in italics, enclosed by angle brackets) of macro descriptions in numerous package documentations is actually produced by a number of special commands, such as
\oarg, provided by the
ltxdoc document class.
The following screenshot is taken from documentation of the
How can I produce the same (or similar) result with normal packages (e.g.
listings) in, say, the
article document class?