cgitrc.5.txt: Add mansource and manmanual.

This prevents FIXMEs from appearing.

Signed-off-by: Loui Chang <louipc.ist@gmail.com>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>

cgitrc.5.txt

@@ -1,3 +1,6 @@
+:man source:   cgit
+:man manual:   cgit
+
 CGITRC(5)
 ========