Append information on markdown formatting in CSV tables to contributor guide

[wwarriner]

Please try to avoid the use of heavily-formatted CSV tables as much as possible. In some cases they are necessary, but require some careful formatting because the markdown linter does not work within CSV files.

• To force text onto a new line use <br> with no surrounding whitespace.
• To force text onto a new line, and indent the new line, use <br>&nbsp; .
  • Note the two trailing spaces!
  • Use two spaces for consistency with unordered lists.
  • Avoid usage of ordered lists and nested lists.
  • If you need intricate formatting, the content may belong outside the table, with a link to the content in the table.
• To create an anchor for use with internal links, surround the leading part of the text with <span id='$anchor-name'>text</span>. Replace $anchor-name with the actual anchor you wish to use in the internal link and HTTPS URL.
  • Only use lowercase letters, numerals, and the dash - character.
  • The dash - character should only be used to separate words, or where a dash or hyphen would normally be placed.
  • Do not use any other punctuation or characters.
  • Make the anchor match the surrounded text.
  • Only surround a small amount of text that "feels" like a header.
  • Example: "Lab PI's" becomes lab-pis.
  • This maintains consistency with section anchors produced by the MkDocs Material theme.