rewrite/flags.xml: Fix reference; Redirect belongs to mod_alias, not core.

module="mod_rewrite">RewriteRule</directive> to be passed back through

URL mapping, so that location-based mappings, such as <directive

module="mod_alias">Alias</directive>, <directive

module="core">Redirect</directive>, or <directive 

module="mod_alias">Redirect</directive>, or <directive 

module="mod_alias">ScriptAlias</directive>, for example, might have a 

chance to take effect.

</p>