project: format R and Rmd using styler

[haraldschilly]

Description

Switch to "styler" to format R code. Also use it to format code inside of Rmd and Rnw...

Help

attempting to format *.rnw files always raises

Error formatting code: 
Error: document not fully opened

which is in the project's format/prettier.ts file. Something must be fundamentally going wrong...

Testing Steps

Relevant Issues

Checklist:

• No debugging console.log messages.
• All new code is actually used.
• Non-obvious code has some sort of comments.

Front end:

• Restart at least one project and check its ~/.smc/local_hub/local_hub.log
• Completely restart Webpack with ./w in /src
• Completely restart the hub by killing and restarting ./start_hub.py in /src/dev/project
• Screenshots if relevant.