hgweb: change manifest archive links to only archive the current directory When the web server shows the manifest for a single, non top directory, append the path to the directory to the archive links. This makes the web server generate archive files that only include the current directory (and its subdirectories). Note that archive links in other pages (e.g. changeset) or at the top of the manifest are unchanged. Directory archive links have an extra "/" at the end which does not impact the result of the archive operation. Keeping it there made the implementation of this feature simpler.