add Jan Rochel to authors

opam

@@ -61,6 +61,7 @@ authors: [
   "Armand Puccetti"
   "Félix Ridoux"
   "Virgile Robles"
+  "Jan Rochel"
   "Muriel Roger"
   "Julien Signoles"
   "Nicolas Stouls"

src/plugins/gui/help_manager.ml

@@ -64,6 +64,7 @@ let show main_ui =
     "Armand Puccetti";
     "Félix Ridoux";
     "Virgile Robles";
+    "Jan Rochel";
     "Muriel Roger";
     "Julien Signoles";
     "Nicolas Stouls";