Various small fixes to resources pages. Small tweaks to code of conduct

[emiliom]

This is a small set of changes. I'm still going over the Resources pages and thinking through some potentially larger changes.

• In resources pages, fixed some warnings and errors involving broken links, an admonition, etc
• Changed the "Resources" menu item to "OHW22 Resources", to make it more overly obvious
• Code of Conduct
  • Tweaked code of conduct text (having nothing to do specifically with Resources pages, though it does involve one Resources page)
    • Changed the wording "report it as soon as possible to one of the instructors" to "report it as soon as possible to one of the organizers or instructors"
    • Added links to two organizations mentioned in the Code of Conduct
  • Added a top-level Code of Conduct menu item in the Resources pages (ok, that's not in this PR at this instant, but I'll push a commit shortly)

[emiliom]

I've also added Resources (now OHW22 Resources) to the ohw22/index.md toctree, so that that page's toctree menu is comprehensive.