fix: yaml-lang-server modelines in init config

[caarlos0]

• docs on how to specify the schema to the lang server
• add it automatically along with vim modelines to the init config
• added it to our config as well

this should prevent some "out of date" schema issues, as well as mixing tabs with spaces and whatnot when an editorconfig plugin is not installed.

[codecov]

Codecov Report

Merging #3376 (956b75b) into main (707747d) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #3376   +/-   ##
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  Coverage   83.85%   83.85%           
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  Files         115      115           
  Lines        9212     9212           
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  Hits         7725     7725           
  Misses       1210     1210           
  Partials      277      277           

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