Fix ---prefix in pkg info manpage

Author: AMDmi3

docs/pkg-info.8

@@ -155,7 +155,7 @@ This option is deprecated and exists only for Ports compatibility.
 Display
 .Ar pkg-name
 origin.
-.It Fl p , --prefix
+.It Fl p , Cm --prefix
 Display the installation prefix for each package matching
 .Ar pkg-name .
 .It Fl F Ar pkg-file , Cm --file Ar pkg-file