trx: Add reference to project wiki page in overfiew section

Change-Id: I83cbd67909c42f4ed4857834e23c07ad4e2e22aa
diff --git a/doc/manuals/chapters/overview.adoc b/doc/manuals/chapters/overview.adoc
index b7d9697..785e26b 100644
--- a/doc/manuals/chapters/overview.adoc
+++ b/doc/manuals/chapters/overview.adoc
@@ -57,3 +57,6 @@
         OsmoTRX [color=red];
 }
 ----
+
+For more information see
+https://osmocom.org/projects/osmotrx/wiki/OsmoTRX