🌐 Sync German docs (#14519)

Sync with #14505 (plus some more)

I actually searched for those patterns in VS Code.

Always:
    files to exclude: README.md, SECURITY.md, llm-prompt.md

This search & replace cleans up the hash parts everywhere under docs/.
It only finds the four occurences in the two _llm-test.md under docs/de/ and docs/pt/

    files to include: docs/**
        Search regex: \{[^\S\n]*#([^\S\n]*[a-z0-9]+(?:-[a-z0-9]+)*)[^\S\n]*\}
        Replace with: { #$1 }

This search finds headings without hash parts. It finds two headings in docs\de\docs\index.md (those which #14505 fixes) and all headings in docs\pt\docs\tutorial\security\index.md, which I also fixed on the way as that document seems to be in sync. docs\pt\docs\index.md is not in Sync, so I didnt touch it.

    files to include: docs/de/**, docs/pt/**
        Search regex: ^(#+)[^\S\n]*([^{}#\s]+(?:[^\S\n]+[^{}\s]+)*)[^\S\n]*(?=\n)
        (added the missing hash parts)

docs/de/docs/index.md

@@ -52,13 +52,13 @@ Seine Schlüssel-Merkmale sind:
 
 <!-- sponsors -->
 
-### Keystone-Sponsor
+### Keystone-Sponsor { #keystone-sponsor }
 
 {% for sponsor in sponsors.keystone -%}
 <a href="{{ sponsor.url }}" target="_blank" title="{{ sponsor.title }}"><img src="{{ sponsor.img }}" style="border-radius:15px"></a>
 {% endfor -%}
 
-### Gold- und Silber-Sponsoren
+### Gold- und Silber-Sponsoren { #gold-and-silver-sponsors }
 
 {% for sponsor in sponsors.gold -%}
 <a href="{{ sponsor.url }}" target="_blank" title="{{ sponsor.title }}"><img src="{{ sponsor.img }}" style="border-radius:15px"></a>