[singlehtml] Remove '/' in section anchorname

And use modified id directly, modified in the previous commit to ensure
unique id in singlehtml.

Author: gastmaier

sphinx/builders/singlehtml.py

@@ -110,7 +110,7 @@ def assemble_toc_secnumbers(self) -> dict[str, dict[str, tuple[int, ...]]]:
         new_secnumbers: dict[str, tuple[int, ...]] = {}
         for docname, secnums in self.env.toc_secnumbers.items():
             for id, secnum in secnums.items():
-                alias = f'{docname}/{id}'
+                alias = f'{docname}{id}'
                 new_secnumbers[alias] = secnum
 
         return {self.config.root_doc: new_secnumbers}

sphinx/writers/html5.py

@@ -395,10 +395,11 @@ def get_secnumber(self, node: Element) -> tuple[int, ...] | None:
         if isinstance(node.parent, nodes.section):
             if self.builder.name == 'singlehtml':
                 docname = self.docnames[-1]
-                anchorname = f'{docname}/#{node.parent["ids"][0]}'
+                # Remove document-
+                anchorname = node.parent['ids'][0][9:]
                 if anchorname not in self.builder.secnumbers:
                     # try first heading which has no anchor
-                    anchorname = f'{docname}/'
+                    anchorname = docname
             else:
                 anchorname = '#' + node.parent['ids'][0]
                 if anchorname not in self.builder.secnumbers: