doc: Use the new doc convention.

The previous few commits are very old, bring them to the new
standards without all the merging conflicts (which are error prone).

docs/common/rules_index.ldoc

@@ -69,4 +69,6 @@
 --   <tr><td><a href='../core_components/client.html#startup_id'>startup\_id</a></td><td>The FreeDesktop StartId</td></tr>
 --   <tr><td><a href='../core_components/client.html#valid'>valid</a></td><td>If the client that this object refers to is still managed by awesome</td></tr>
 --   <tr><td><a href='../core_components/client.html#first_tag'>first\_tag</a></td><td>The first tag of the client</td></tr>
+--   <tr><td><a href='../core_components/client.html#buttons'>buttons</a></td><td>Get or set mouse buttons bindings for a client</td></tr>
+--   <tr><td><a href='../core_components/client.html#keys'>keys</a></td><td>Get or set keys bindings for a client</td></tr>
 -- </table>

lib/awful/button.lua

@@ -103,7 +103,7 @@ button.names = {
 -- @param function
 
 --- Execute this mousebinding.
--- @function button:trigger
+-- @method :trigger
 
 function button:set_button(b)
     for _, v in ipairs(self) do