[fc-lang] introduce public git repo

_fc-plugins/frama-clang.md

@@ -46,6 +46,9 @@ please consult the [Frama-Clang manual]({{page.manual_pdf}}).
 The current version is 0.0.11. The frama-clang plugin can be downloaded
 [here](/download/frama-clang-0.0.11.tar.gz).
 
+Frama-Clang also has its own public git [repository](https://git.frama-c.com/pub/frama-clang),
+whose `master` branch should always be synchronized with Frama-C's own `master` branch.
+
 ### Requirements
 
 - Frama-C 23.x Vanadium