add rewrite rule for css-namespaces-3

Author: Peter Linss

.htaccess

@@ -146,6 +146,7 @@ RewriteRule ^css-lists-3/(.*)$ css-lists/$1
 RewriteRule ^css-logical-props-1/(.*)$ css-logical-props/$1
 RewriteRule ^css-multicol-1/(.*)$ css-multicol/$1
 RewriteRule ^css-namespaces-1/(.*)$ css-namespaces/$1
+RewriteRule ^css-namespaces-3/(.*)$ css-namespaces/$1
 RewriteRule ^css-overflow-3/(.*)$ css-overflow/$1
 RewriteRule ^css-page-3/(.*)$ css-page/$1
 RewriteRule ^css-page-template-1/(.*)$ css-page-template/$1