util: Improve documentation of wl_iterator_result

Use declarative voice, remove the unnecessary doxygen \enum tag, and add
two see-also's. This keeps the output the same but makes the comment
voice consistent, a little more readable, and refers to documented
functions that use this enum type.

Signed-off-by: Yong Bakos <ybakos@humanoriented.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
diff --git a/src/wayland-util.h b/src/wayland-util.h
index 8b02ff0..2fd99a0 100644
--- a/src/wayland-util.h
+++ b/src/wayland-util.h
@@ -684,9 +684,11 @@
 
 typedef void (*wl_log_func_t)(const char *, va_list) WL_PRINTF(1, 0);
 
-/** \enum wl_iterator_result
+/**
+ * Return value of an iterator function
  *
- * This enum represents the return value of an iterator function.
+ * \sa wl_client_for_each_resource_iterator_func_t
+ * \sa wl_client_for_each_resource
  */
 enum wl_iterator_result {
 	/** Stop the iteration */