Reboot: remove textarea -webkit-appearance: textfield

[csabaxyz]

I was playing around with reboot and Chrome threw me a warning saying:

[Deprecation] '-webkit-appearance: textfield' for elements other than input[type=email], input[type=number], input[type=password], input[type=search], input[type=tel], input[type=text], input[type=url], input[type=date], input[type=datetime-local], input[type=month], input[type=time], and input[type=week] is deprecated and will be removed in M79, around December 2019. See https://www.chromestatus.com/features/5070237827334144 for more details.

It is related to this line:

bootstrap/scss/_reboot.scss

Line 473 in 129bb08

-webkit-appearance: textfield; // 3

Also, this line actually caused an issue in Firefox, when I tried to use reboot without any other Bootstrap related textarea styling, because if no border is set then the textarea has an 8px weird border. I'm saying weird, because it actually shows up as a padding and makes the resize handle incorrectly positioned.

I'm using Arch Linux, Arc theme, although, as far as I know, Firefox now uses the Adwaita theme to render the inputs.

Defining a border removes this padding.