DOC: mention the "lua action" in documentation

Fix some precision about lua.

doc/configuration.txt

@@ -8208,6 +8208,7 @@ tcp-request content <action> [{if | unless} <condition>]
     - reject : the request is rejected and the connection is closed
     - capture : the specified sample expression is captured
     - { track-sc0 | track-sc1 | track-sc2 } <key> [table <table>]
+    - lua <function>
 
   They have the same meaning as their counter-parts in "tcp-request connection"
   so please refer to that section for a complete description.
@@ -8389,6 +8390,9 @@ tcp-response content <action> [{if | unless} <condition>]
         or false (when used with "unless"). The first such rule executed ends
         the rules evaluation. Rejected session are immediately closed.
 
+    - lua <function>
+        Executes Lua.
+
   Note that the "if/unless" condition is optional. If no condition is set on
   the action, it is simply performed unconditionally. That can be useful for
   for changing the default action to a reject.