Set pageurl through get_target_uri in StandaloneHTMLBuilder (#9731)

Co-authored-by: Adam Turner <[email protected]>

sphinx/builders/html/__init__.py

@@ -1063,7 +1063,7 @@ def handle_page(
 
         if self.config.html_baseurl:
             ctx['pageurl'] = posixpath.join(
-                self.config.html_baseurl, pagename + self.out_suffix
+                self.config.html_baseurl, self.get_target_uri(pagename)
             )
         else:
             ctx['pageurl'] = None