[doc] document journal display

data/actionsmap/yunohost.yml

@@ -1608,7 +1608,7 @@ journals:
 
         ### journals_display()
         display:
-            action_help: List journals
+            action_help: Display a journal content
             api: GET /journals/<file_name>
             arguments:
                 file_name:

src/yunohost/journals.py

@@ -74,6 +74,13 @@ def journals_list(limit=None):
 
 
 def journals_display(file_name):
+    """
+    Display a journal content
+
+    Argument:
+        file_name
+    """
+
     if not os.path.exists(JOURNALS_PATH):
         # TODO raise exception
         return {}