Updated System18 (markdown)
Added rules for Britain
Added rules for Mississippi
Add rules clarification with link to designer's post about rusting schedule typos
add podcast: Choo Choo Crew
Updated 18xx Online Communities, Media, and Resources (markdown)
fix formatting
`docker-compose` -> `docker compose`
update channels to match style throughout page
Updated 18JPT (markdown)
improve formatting
capitalise 'G' in 18xx.Games to indicate it is a 'brand'.
improve img title
further improve formatting
Updated Individual Statistics (markdown)
take 18xx.games out of code element
Add warning for Google Chat instructions
link first instance of 1830, improve clarity
use details element - helps accessibility
Add trailing whitespace back in for TOC