gmain: Convert docs to markdown

In particular, convert lists to markdown syntax.

glib/gmain.c

@@ -2823,26 +2823,17 @@ get_dispatch (void)
  * many things that the user could do. Instead, you can use the
  * following techniques:
  *
- * <orderedlist>
+ * 1. Use gtk_widget_set_sensitive() or modal dialogs to prevent
- *  <listitem>
- *   <para>
- *     Use gtk_widget_set_sensitive() or modal dialogs to prevent
  *    the user from interacting with elements while the main
  *    loop is recursing.
- *   </para>
+ * 
- *  </listitem>
+ * 2. Avoid main loop recursion in situations where you can't handle
- *  <listitem>
- *   <para>
- *     Avoid main loop recursion in situations where you can't handle
  *    arbitrary  callbacks. Instead, structure your code so that you
  *    simply return to the main loop and then get called again when
  *    there is more work to do.
- *   </para>
- *  </listitem>
- * </orderedlist>
  * 
  * Return value: The main loop recursion level in the current thread
- **/
+ */
 int
 g_main_depth (void)
 {