Improve docs for ky.stop

[ialexi-bl]

Fixes #290. I would also like to add console.warn in shortcut methods, such as .json() and .text() that would display a warning when ky.stop is returned and these methods are used. Maybe a lazy solution to check if this result is not undefined could work:

ky/index.js

Line 338 in d976029

const result = isRetriableMethod ? this._retry(fn) : fn();

I can definitely add a check that it's not undefined to prevent those from throwing TypeError and to make them silently return undefined instead. The question is: is it guaranteed that if result is undefined, this was caused by ky.stop? If yes, I could also add console.warn in the same place where this check for result !== undefined is performed.

[sindresorhus]

index.d.ts should be in sync with the readme.

[ialexi-bl]

I would also suggest to change tabs in code snippets in readme to spaces, because they are pretty hard to read with many levels of nesting, considering how wide tabs on github are. Maybe in a different PR though

[sindresorhus]

I would also suggest to change tabs in code snippets in readme to spaces, because they are pretty hard to read with many levels of nesting, considering how wide tabs on github are. Maybe in a different PR though

No thanks :)