can not use the same name of header in post

when i use the same name as bellows:
```
1. Header1
1.1 aa
1.2 bb
2. Header2
2.1 aa
```
1.1 and 2.1 use the same name `aa`, but it didn't work when I click 2.1

Reproduce the issue with the numbered headings shown in the report and inspect how the plugin generates links for repeated heading names. Confirm that clicking the second “aa” navigates to the second heading rather than the first, and verify the behavior with a regression test if the project’s test entry point is identified.

Written by the indexing model from the issue text.