environment: Change VCS log view URL for Savannah.

* guix/jupyter/environment.scm (%vcs-web-views): Change URL for Savannah
commit logs.

guix/jupyter/environment.scm

@@ -97,7 +97,7 @@ of the SPECS could not be resolved."
        ,(lambda (repository-url commit)
           (string-append (string-replace-substring repository-url
                                                    "/git/" "/cgit/")
-                         "/commit/?id=" commit)))
+                         "/log/?id=" commit)))
       ("notabug.org" ,labhub-url)
       ("framagit.org" ,labhub-url)
       ("gitlab.com" ,labhub-url)