message: eliminate 'git diff ---check' false alarms for Markdown files
diff: # reST underlines/overlines can look like conflict markers
  *.rst text conflict-marker-size=80
  +# Markdown heading markers can look like conflict markers
  +*.md text conflict-marker-size=200
  *.cmake text whitespace=tabwidth=2
  *.cmakein text whitespace=tabwidth=2
  