man: Use debian/control as the SYNOPSIS in deb-src-control(5)

debian/changelog

@@ -5,6 +5,7 @@ dpkg (1.18.10) UNRELEASED; urgency=medium
     - Document Testsuite-Triggers in dsc(5).
     - Fix deb-changes(5) description to talk about .changes instead of .dsc.
       Reported by HW42 <hw42@ipsumj.de>.
+    - Use debian/control as the SYNOPSIS in deb-src-control(5).
 
   [ Updated scripts translations ]
   * German (Helge Kreutzmann).

man/deb-src-control.5

@@ -22,7 +22,7 @@
 deb\-src\-control \- Debian source packages' master control file format
 .
 .SH SYNOPSIS
-control
+debian/control
 .
 .SH DESCRIPTION
 Each Debian source package contains the master \(Focontrol\(Fc file,