fix bigpage filename in HomePage.pod6

Author: mendel

doc/HomePage.pod6

@@ -3,7 +3,7 @@
 Welcome to the official documentation of the <a href="https://raku.org">Raku</a>
 programming language!
 Besides online browsing and searching, you can also
-<a href="/perl6.html">view everything in one file</a> or
+<a href="/raku.html">view everything in one file</a> or
 <a href="https://github.com/Raku/doc">contribute</a>
 by reporting issues or sending patches.