Document is confusing, references ajax but example uses atomic

In the README, the Options and Settings section says:
```
Atomic includes smart defaults and works right out of the box. You can pass options into Atomic
through the ajax() function:
```
but the example doesn't mention ajax:

```
atomic('https://s...
```

Should ajax() be atomic()?

-- rouilj

Open the README and inspect the Options and Settings section, especially the text mentioning ajax() and the adjacent atomic('https://s...') example. Compare the function name in the prose with the example and update the documentation so they are consistent; the issue is done when the section no longer references the wrong entry point.

Written by the indexing model from the issue text.