man: Clarify that an architecture wildcard is a Debian thing

debian/changelog

@@ -11,6 +11,8 @@ dpkg (1.18.2) UNRELEASED; urgency=low
     - Document --yet-to-unpack, --predep-packages and all --assert-<feature>
       commands as supported in both «dpkg --help» and dpkg(1).
     - Document abitable in dpkg-architecture(1).
+    - Clarify that an architecture wildcard is a Debian thing in
+      dpkg-architecture(1).
 
   [ Updated programs translations ]
   * Dutch (Frans Spiesschaert). Closes: #789097

man/dpkg-architecture.1

@@ -139,8 +139,8 @@ The machine the compiler is building for.
 .IP "Debian architecture" 4
 The Debian architecture string, which specifies the binary tree in the
 FTP archive. Examples: i386, sparc, hurd\-i386.
-.IP "architecture wildcard" 4
-An architecture wildcard is a special architecture string that will match
+.IP "Debian architecture wildcard" 4
+A Debian architecture wildcard is a special architecture string that will match
 any real architecture being part of it. The general form is <kernel>\-<cpu>.
 Examples: linux\-any, any\-i386, hurd\-any.
 .IP "GNU system type" 4