fix: remove hiding scrollbar on hover and optimize input lag in the home page search box.

[gjssss]

Hi, antfu !! @antfu I am your fans !!

• I found the page will unfriendly shake when quickly hovering and not hovering.
• There is noticeable lag when inputting in the home page's input box. Here is the problem

https://github.com/antfu/icones/assets/74909529/e505717d-0fc2-4782-ab41-c8be5d1ed17b

In the video, I try to delete the word in the search input, but it is not work. So I add a debounce, it makes the page start to compute the filter array when typing stops some time.

I didn't find any obvious lag when typing in other search boxes, so I only modified this one.

Thank you !!!!!

Please give me some advice !

[antfu]

Thanks!