Before:
  runtime ale_linters/markdown/remark_lint.vim

Execute(Warning and error messages should be handled correctly):
  AssertEqual
  \ [
  \   {
  \      'lnum': 1,
  \      'col': 4,
  \      'type': 'W',
  \      'text': 'Incorrect list-item indent: add 1 space  list-item-indent  remark-lint',
  \   },
  \   {
  \      'lnum': 3,
  \      'col': 5,
  \      'type': 'E',
  \      'text': 'Incorrect list-item indent: remove 1 space  list-item-indent  remark-lint',
  \   },
  \ ],
  \ ale_linters#markdown#remark_lint#Handle(1, [
  \   'foo.md',
  \   '  1:4  warning  Incorrect list-item indent: add 1 space  list-item-indent  remark-lint',
  \   '  3:5  error  Incorrect list-item indent: remove 1 space  list-item-indent  remark-lint',
  \   '',
  \   '⚠ 1 warnings',
  \   '✘ 1 errors',
  \])