[frogr] Add missing id parameters to <section>s so yelp-check validates

[Andre Klapper <aklapper src gnome org>]

commit ed4ca37de5b1eb3b14a950370c5322b1cccbc319
Author: Andre Klapper <a9016009 gmx de>
Date:   Thu Sep 28 19:39:49 2017 +0200

    Add missing id parameters to <section>s so yelp-check validates

 help/C/introduction.page |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/help/C/introduction.page b/help/C/introduction.page
index aa1e1bd..f6cb79d 100644
--- a/help/C/introduction.page
+++ b/help/C/introduction.page
@@ -19,11 +19,11 @@
     </media>
   </figure>
 
-  <section><title>Flickr</title>
+  <section id="flickr"><title>Flickr</title>
     <p><link href="http://www.flickr.com/";>Flickr</link> is a website allowing hosting of both images and 
videos.</p>
   </section>
 
-  <section><title>Main features</title>
+  <section id="main-features"><title>Main features</title>
     <list>
       <item><p>Allow to upload pictures and videos to Flickr</p></item>
       <item><p>Allow uploading pictures located in remote machines</p></item>
@@ -34,7 +34,7 @@
     </list>
   </section>
 
-  <section><title>About</title>
+  <section id="about"><title>About</title>
     <p>You can have more information about <app>frogr</app> using the menu 
<guiseq><gui>frogr</gui><gui>About</gui></guiseq>.</p>
   </section>