Fix circular dependencies

[gwdawson]

Before:

src/parser.js, src/exports.js → ./dist/index.cjs, ./dist/index.es.js...
(!) Circular dependency
src/formatter/formatter.js -> src/formatter/metrics.js -> src/formatter/formatter.js
created ./dist/index.cjs, ./dist/index.es.js in 80ms

After:

src/parser.js, src/exports.js → ./dist/index.cjs, ./dist/index.es.js...
created ./dist/index.cjs, ./dist/index.es.js in 77ms