src/xbps/index.md: Link to void-packages/Manual.md

Add link to instructions for creating new packages.

Author: camoz

src/xbps/index.md

@@ -30,10 +30,14 @@ Most general package management is done with the following commands:
 Most questions can be answered by consulting the man pages for these tools,
 together with the [xbps.d(5)](https://man.voidlinux.org/xbps.d.5) man page.
 
-To learn how to build packages from source, refer to [the README for the
+To learn how to build packages from source, refer to [the README of the
 void-packages
 repository](https://github.com/void-linux/void-packages/blob/master/README.md).
 
+To learn how to create new packages, refer to [the Manual of the
+void-packages
+repository](https://github.com/void-linux/void-packages/blob/master/Manual.md).
+
 ## Updating
 
 Like any other system, it is important to keep Void up-to-date. Use