[Bug]: Section indexes should only render headers below the current place

[brotkrueml]

Summary

In Sphinx-based rendering section indexes hold only the anchors below the current place, for example:

https://docs.typo3.org/m/typo3/reference-tsconfig/12.4/en-us/UserTsconfig/Options.html

PHP-based rendering seems to take all headers into account:

https://docs.typo3.org/m/typo3/reference-tsconfig/main/en-us/UserTsconfig/Options.html

MInd the additional "Properties" anchor in the last example.

Code snippet that reproduces the problem

Properties
==========

..  contents::
    :depth: 2
    :local:

additionalPreviewLanguages
--------------------------

some text

alertPopups
-----------

another text

should not render "Properties"

Expected output

• additionalPreviewLanguages
• alertPopups

[linawolf]

... if :local: is set