man: Add references to man pages describing file formats

debian/changelog

@@ -3,6 +3,7 @@ dpkg (1.18.5) UNRELEASED; urgency=medium
   * Documentation:
     - Say value instead of option in deb-control(5).
     - Mark debian changelog format in bold in dpkg-parsechangelog(1).
+    - Add references to man pages describing file formats.
 
  -- Guillem Jover <guillem@debian.org>  Fri, 25 Dec 2015 14:20:16 +0100
 

man/dpkg-genchanges.1

@@ -174,3 +174,9 @@ prepared.
 reads the data here when producing a
 .B .changes
 file.
+.
+.SH SEE ALSO
+.ad l
+.nh
+.BR deb\-substvars (5),
+.BR deb\-src\-control (5).

man/dpkg-gencontrol.1

@@ -158,3 +158,9 @@ prepared.
 .B dpkg\-gencontrol
 adds the presumed filenames of binary packages whose control files it
 generates here.
+.SH SEE ALSO
+.ad l
+.nh
+.BR deb\-substvars (5),
+.BR deb\-src\-control (5),
+.BR deb\-control (5).

man/dpkg-source.1

@@ -810,6 +810,9 @@ start of a comment up to the end of line).
 The point at which field overriding occurs compared to certain
 standard output field settings is rather confused.
 .SH SEE ALSO
+.ad l
+.nh
+.BR deb\-src\-control (5),
 .BR dpkg\-deb (1),
 .BR dpkg (1),
 .BR dselect (1).