Ship deb-split man page in dpkg-dev package

debian/dpkg-dev.install

@@ -23,6 +23,7 @@ usr/share/man/{*/*,*}/deb-substvars.5
 usr/share/man/{*/*,*}/deb-override.5
 usr/share/man/{*/*,*}/deb-extra-override.5
 usr/share/man/{*/*,*}/deb-shlibs.5
+usr/share/man/{*/*,*}/deb-split.5
 usr/share/man/{*/*,*}/deb-symbols.5
 usr/share/man/{*/*,*}/deb-triggers.5
 usr/share/man/{*/*,*}/deb-old.5