Typing in autosize textarea triggers scrolling to top of browser window #212

First of all thanks for this library, it is really useful!

However I noticed a problem with the autosize textarea, here are the steps to reproduce:

1. Launch the use_textarea_autosize example
2. Fill the textarea with enough content that it is higher than the browser window, and a scrollbar appears from the browser (its enough to hold Enter for some seconds)
3. Move cursor to middle of textarea
4. Type something

You will notice that the scroll position is changed, it goes up to the top of the page. I would expect the scroll position to remain unchanged.