Do not specify a line/char for prettier when not apropriate

Summary:
This makes the output super weird for no reason whatsoever as orettier error messages already point to the right location.

I also fixed the indentation that was weird. I was unable to run phpcs as it exploded in my face, so I ended up not.

Test Plan:
Edit web/docs/package.json to make it invalid.
Run arc lint
Check the output makes more sense.

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D9840