style: Disable line length limit for Markdown files

This allows to use the one sentence per line formatting to avoid that
changing one sentence requires reformatting a whole paragraph.

Signed-off-by: Martin Nonnenmacher <[email protected]>

Author: mnonnenmacher

.markdownlint.yaml

@@ -6,10 +6,7 @@ MD004:
   style: asterisk
 
 # line-length
-MD013:
-  code_blocks: false
-  line_length: 120
-  tables: false
+MD013: false
 
 # no-duplicate-heading
 MD024: false # GitHub has no issues with anchors for headings with the same content.