doc: Added \code tags around sample code in doxygen comments

Also removed \comment and used C++ comments. There does not appear
to be any other way to put comments into code samples.

Reviewed-by: Bryce Harrington <b.harrington@samsung.com>

src/wayland-client.c

@@ -1326,10 +1326,12 @@ wl_display_prepare_read_queue(struct wl_display *display,
  * it will assume the file descriptor is readable and read events from
  * the fd by calling wl_display_dispatch().  Simplified, we have:
  *
- *   wl_display_dispatch_pending(display);
- *   wl_display_flush(display);
- *   poll(fds, nfds, -1);
- *   wl_display_dispatch(display);
+ * \code
+ * wl_display_dispatch_pending(display);
+ * wl_display_flush(display);
+ * poll(fds, nfds, -1);
+ * wl_display_dispatch(display);
+ * \endcode
  *
  * There are two races here: first, before blocking in poll(), the fd
  * could become readable and another thread reads the events.  Some of
@@ -1344,13 +1346,14 @@ wl_display_prepare_read_queue(struct wl_display *display,
  * fds in the event loop.
  *
  * A correct sequence would be:
- *
- *   while (wl_display_prepare_read(display) != 0)
- *           wl_display_dispatch_pending(display);
- *   wl_display_flush(display);
- *   poll(fds, nfds, -1);
- *   wl_display_read_events(display);
- *   wl_display_dispatch_pending(display);
+ * \code
+ * while (wl_display_prepare_read(display) != 0)
+ *         wl_display_dispatch_pending(display);
+ * wl_display_flush(display);
+ * poll(fds, nfds, -1);
+ * wl_display_read_events(display);
+ * wl_display_dispatch_pending(display);
+ * \endcode
  *
  * Here we call wl_display_prepare_read(), which ensures that between
  * returning from that call and eventually calling

src/wayland-server.h

@@ -144,18 +144,18 @@ wl_client_post_no_memory(struct wl_client *client);
  * listener should be done through provided accessor methods. A listener can
  * only listen to one signal at a time.
  *
- * ~~~
+ * \code
  * struct wl_listener your_listener;
  *
  * your_listener.notify = your_callback_method;
  *
- * \comment{Direct access}
+ * // Direct access
  * wl_signal_add(&some_object->destroy_signal, &your_listener);
  *
- * \comment{Accessor access}
+ * // Accessor access
  * wl_event_loop *loop = ...;
  * wl_event_loop_add_destroy_listener(loop, &your_listener);
- * ~~~
+ * \endcode
  *
  * If the listener is part of a larger struct, #wl_container_of can be used
  * to retrieve a pointer to it:

src/wayland-util.h

@@ -88,8 +88,7 @@ struct wl_interface {
  * "item_t", and the item member as "struct wl_list link".
  *
  * The following code will initialize a list:
- *
- * ~~~
+ * \code
  * struct wl_list foo_list;
  *
  * struct item_t {
@@ -99,20 +98,19 @@ struct wl_interface {
  * struct item_t item1, item2, item3;
  *
  * wl_list_init(&foo_list);
- * wl_list_insert(&foo_list, &item1.link);   \comment{Pushes item1 at the head}
- * wl_list_insert(&foo_list, &item2.link);   \comment{Pushes item2 at the head}
- * wl_list_insert(&item2.link, &item3.link); \comment{Pushes item3 after item2}
- * ~~~
+ * wl_list_insert(&foo_list, &item1.link);	// Pushes item1 at the head
+ * wl_list_insert(&foo_list, &item2.link);	// Pushes item2 at the head
+ * wl_list_insert(&item2.link, &item3.link);	// Pushes item3 after item2
+ * \endcode
  *
  * The list now looks like [item2, item3, item1]
  *
- * Will iterate the list in ascending order:
- *
+ * Iterate the list in ascending order:
  * \code
- * item_t *item;
- * wl_list_for_each(item, foo_list, link) {
- * 	Do_something_with_item(item);
- * }
+ *	item_t *item;
+ *	wl_list_for_each(item, foo_list, link) {
+ *		Do_something_with_item(item);
+ *	}
  * \endcode
  */
 struct wl_list {
@@ -138,10 +136,10 @@ void wl_list_insert_list(struct wl_list *list, struct wl_list *other);
  * To demonstrate, the following example retrieves a pointer to
  * `example_container` given only its `destroy_listener` member:
  *
- * ~~~
+ * \code
  * struct example_container {
  *     struct wl_listener destroy_listener;
- *     \comment{other members...}
+ *     // other members...
  * };
  *
  * void example_container_destroy(struct wl_listener *listener, void *data)
@@ -149,9 +147,9 @@ void wl_list_insert_list(struct wl_list *list, struct wl_list *other);
  *     struct example_container *ctr;
  *
  *     ctr = wl_container_of(listener, ctr, destroy_listener);
- *     \comment{destroy ctr...}
+ *     // destroy ctr...
  * }
- * ~~~
+ * \endcode
  *
  * \param ptr A valid pointer to the contained item.
  *