[ltest] Add reference to pathcrawler

_fc-plugins/ltest.md

@@ -23,6 +23,11 @@ covered for a given criterion. In this context,
 - `LReplay` executes a test suite over some code instrumented with
   (hyper)labels and computes a coverage ratio.
 
+On the other hand, these component, and notably `LReplay` assume that you
+already have a test suite whose coverage you want to evaluate. Still in the
+context of Frama-C, you can for instance use
+[PathCrawler]({% link _fc-plugins/pathcrawler.md %}) to generate such a suite.
+
 ## Further Reading
 
 - Sébastien Bardin, Nikolai Kosmatov, Michaël Marcozzi, and Mickaël Delahaye.