Update typography reference

Use Damien Jullemier's personal web site because its URL persistence
policy is more reliable than Unicode's (who deleted the page we
previously used a as reference).

css-text-4/Overview.bs

@@ -8130,7 +8130,7 @@ Character Class Spacing: the 'text-spacing' property</h3>
 
 			In this level, if the element's content language is French,
 			narrow no-break space (U+202F) and no-break space (U+00A0) is inserted
-			where required by <a href="http://unicode.org/udhr/n/notes_fra.html">French typographic guidelines</a>.
+			where required by <a href="http://damien.jullemier.pagesperso-orange.fr/typ/typ-espace-ponctuation.htm">French typographic guidelines</a>.
 			Otherwise this value has no effect.
 			However future specifications may add automatic spacing behavior for other languages.