skins2: fix typo in documentation

it should read 'TL/TL and BR/BL' instead of 'TL/TL and TL/BL'

doc/skins/skins2-howto.xml

@@ -1198,7 +1198,7 @@ difficulty to understand how VLC skins work.</para>
 <para>A box inside a container box always defines how it should react when its container box is resized. Two different mechanisms are provided: corners anchoring (useful when resizing of the inner box is wanted, for example) and constant ratio (mainly useful to keep the inner box centered inside its parent):</para>
 <itemizedlist>
   <listitem><para>
-    <emphasis>corners anchoring</emphasis>: The top-left-hand corner (TL) and the bottom-right-hand corner (BR) of the inner box are "tied" to corners of the container box (TL, TR, BL or BR). When any resizing occurs, tied corners move together, which can move or resize the inner box. For example, if the TL corner of the inner box is tied to the TL corner of the container (let's write it TL/TL), and if the BR corner of the inner box is also tied to the TL corner of the container box (BR/TL), the inner box will not be resized, and will always stay at the same place (this is the default behaviour). If we have TL/TL and TL/BL, the inner box is resized vertically when its container is resized. If we have TL/TR and BR/TR, the inner box moves with the TR corner of its container. We could even define TL/BR and BR/TL, in which case increasing the size of the container box would shrink the size of the inner box... until it disappears completely!
+    <emphasis>corners anchoring</emphasis>: The top-left-hand corner (TL) and the bottom-right-hand corner (BR) of the inner box are "tied" to corners of the container box (TL, TR, BL or BR). When any resizing occurs, tied corners move together, which can move or resize the inner box. For example, if the TL corner of the inner box is tied to the TL corner of the container (let's write it TL/TL), and if the BR corner of the inner box is also tied to the TL corner of the container box (BR/TL), the inner box will not be resized, and will always stay at the same place (this is the default behaviour). If we have TL/TL and BR/BL, the inner box is resized vertically when its container is resized. If we have TL/TR and BR/TR, the inner box moves with the TR corner of its container. We could even define TL/BR and BR/TL, in which case increasing the size of the container box would shrink the size of the inner box... until it disappears completely!
   </para>
   <para>This mechanism is controlled by the <link linkend="lefttop">lefttop</link> and <link linkend="rightbottom">rightbottom</link> attributes of the controls.
   </para></listitem>