perf(markdown): replace scroll util with native element.scrollIntoView

[Luca Ban]

use
element.scrollIntoView({ behavior: "smooth" })

https://developer.mozilla.org/en-US/docs/Web/API/Element/scrollIntoView

write in component README (jsdoc above export default) that safari needs polyfill:
https://github.com/iamdustan/smoothscroll

and example of how to install it.

[Luca Ban]

this is not yet necessary, 'cause it sounds just like a time suck without that much benefit