chore: Improve german translation

[Dosenpfand]

Description

For the german translation:

1. Fix mistakes
2. Add missing
3. Improve the wording

[codecov]

Codecov Report

Merging #1872 (15ec602) into master (54f8a7b) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1872   +/-   ##
=======================================
  Coverage   77.64%   77.64%           
=======================================
  Files          70       70           
  Lines        8556     8556           
=======================================
  Hits         6643     6643           
  Misses       1913     1913           

Flag	Coverage Δ
python	77.64% <ø> (ø)

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[dpgaspar]

Thank you @Dosenpfand