Retrieves all the innerHTML from elements located by CSS or XPath and returns it to test.
Resumes test execution, so **should be used inside async function with `await`** operator.

```js
let postHTMLs = await I.grabHTMLFromAll('.post');
```

@param {CodeceptJS.LocatorOrString} element located by CSS|XPath|strict locator.
@returns {Promise<string[]>} HTML code for an element