shell: advertise lisa-test

The lisa-shell has a lisa-test command.  It's in its early stages but
it's useful in its current form so start advertising it.
diff --git a/LisaShell.txt b/LisaShell.txt
index 23e5b79..1eb9fa5 100644
--- a/LisaShell.txt
+++ b/LisaShell.txt
@@ -26,3 +26,8 @@
 
 lisa-report  - Pretty format results of last test
 
+.:: Test commands
+--------------------------------------
+
+lisa-test    - Run tests and assert behaviours
+