[css2] fix grammar

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extra : convert_revision : svn%3A73dc7c4b-06e6-40f3-b4f7-9ed1dbc14bfc/trunk%402367

Author: fantasai

css2/issues/issues-3

@@ -1704,8 +1704,7 @@ http://www.w3.org/TR/CSS21/visuren.html#direction
 Append to this paragraph:
    | This exception includes UAs that render right-to-left characters
    | simply because a font on the system contains them but do not
-   | support the concept of right-to-left text direction are exempt
-   | from this requirement.
+   | support the concept of right-to-left text direction.
 which is lifted from the end of the fourth paragraph in this section.
 
    # The characters in certain scripts are written from right to left