R16 description and example of backticks in markdown

R16 description.txt

An instance of R16 `!rkt`, the Racket ‘trick-bot’, can be used to run short pieces of code.   
Use `!rkt help` for the full list of commands.


You can include clode blocks by putting three backticks (\`\`\`) on the lines before and after: 
```scheme
`​`​`scheme
(define (myfun a)
  (+ 1 a))
`​`​`
```