Fix markdown linter errors

[apainintheneck]

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---

v0.13 of the markdownlint gem just got released and it has a few new rules which our docs ended up failing. This fixes those linter errors so that CI is no longer red.

Rules:
MD055 - Tables: Each row must start and end with a '|'
MD057 - Tables: In the second row every column must have at least '---',
possibly surrounded with alignment ':' chars

Related to: #16070

For the curious, this is how you can fix the MD055 linter error. It doesn't seem like this linter has a built-in fix option.

$ gawk -i inplace '
BEGIN {
  cmd = "bundle exec rake lint"
  while((cmd | getline line) > 0) {
    split(line, arr, ":")
    filename = arr[1]
    if(filename !~ /\.md$/) continue

    lineno = arr[2]
    if(lineno !~ /^[0-9]+$/) continue

    error = arr[3]
    if(error !~ /^ MD[0-9][0-9][0-9]/) continue

    files[filename] = 1
    lines[filename, lineno] = error
  }
  close(cmd)

  for(filename in files) ARGV[ARGC++] = filename
}

files[FILENAME] && lines[FILENAME, FNR] ~ /MD055/ {
  sub(/^[ ]*\|[ ]*/, "")
  sub(/[ ]*\|[ ]*$/, "")
  printf("| %s |\n", $0)
  next
}

{ print }
'

[MikeMcQuaid]

Looks great, thanks again @apainintheneck and particularly for the PR and quick turnaround here.

[buildpulse]

Known disruptive tests have failed for this pull request.

Commit SHA: d0eef12
Build URL: https://github.com/Homebrew/brew/actions/runs/6392568960/attempts/1

Suite Name	Test Name	Details
rspec	SystemCommand with both STDOUT and STDERR output from upstream with print_stdout its result stderr is expected to eq "2\n4\n6\n"	→

[EricFromCanada]

I'd have simply disabled rule MD055 in docs/.mdl_style.rb, since leading and trailing pipes are not required for GitHub Flavored Markdown.

[apainintheneck]

@EricFromCanada Feel free to change it if you think it's important. I was having fun using awk so I wasn't thinking about if there was a better way to handle this.

[EricFromCanada]

@apainintheneck ¯\_(ツ)_/¯