test: ensure our docs are up-to-date

doc: suggest setting flags only for run

Fixes #10

fix: go_sdk is external

Fixes a missing runfiles lookup when used in a downstream project

feat: support gofmt

Update README.md

Note about don't abuse extensions for files that aren't actually that language

fix: use swiftformat_mac repo on darwin

fix: correct github repo name

ci: make e2e test pass