Those are redundant, and yaml parser strips them in fact. By removing
them, loading and saving yaml file without any change indeed produce the
same output. This is useful for prepare_for_translation.py script (which
adds lang and ref tags) - to produce only change that indeed was made.
Those are fields used by the language switcher to correlate pages across
different languages, even if they have different names/paths/titles.
They are generated with the prepare_for_translation.py script.
- mark all code blocks with ```
- unify empty lines between sections
- adjust list syntax (no space before dash)
- adjust headers to use Atx-style syntax
- remove trailing spaces
