* lisp/ox-publish.el (org-publish-sitemap): Remove property.
* doc/org.texi (Sitemap):
* lisp/ox-publish.el (org-publish-project-alist): Remove documentation.
Caches uses absolute file names as keys. We cannot provide file names
without extension to `:sitemap-format-entry' as they are no longer
existing key, and cannot be used for `org-publish-find-property' or
`org-publish-find-title'.