[css2] Add missing period.

--HG--
extra : convert_revision : svn%3A73dc7c4b-06e6-40f3-b4f7-9ed1dbc14bfc/trunk%403096

Author: fantasai

css2/generate.src

@@ -899,7 +899,7 @@ principal block box. Values have the following meanings:</p>
 
 <dd>The marker box is outside the principal block box. <!--86-->The
 position of the list-item marker adjacent to floats is undefined in
-CSS&nbsp;2.1<!--/86--> CSS&nbsp;2.1 does not specify the precise
+CSS&nbsp;2.1.<!--/86--> CSS&nbsp;2.1 does not specify the precise
 location of the marker box <!--191-->or its position in the painting
 order<!--/191-->, but does
 require that for list items whose 'direction' property is 'ltr' the