Name already in use

The results for computed `line-height` in #593 were virtually different in all tested browsers, and since [such browsers are ones we support](https://github.com/necolas/normalize.css#browser-support), I don't see the need to have a *complex* comment naming all of them.

Resolves #581

After modifying search input with -webkit-appearance: textfield, the
focus outline is remaining with `outline-offset: 0`, but should be
`-2px` like other textfield inputs.

Limit Firefox focus normalization to buttons

Spacing does not need to be normalized for all `input` elements in
Firefox, only `button` and `[type="button"]` elements. These
normalizations were changing the default focus appearance of `input`
elements.

Resolves #549

Correct the text style of placeholders in Chrome, Edge, and Safari

Remove overflow from select and update multiple overflow

Normalizes placeholder styles in Edge, Chrome, and Safari with Firefox.

While the consistent `overflow` for `select` is `visible`, updating
this property has no effect in any browser, but instead creates an
inappropriately visible overflow for `select[multiple]`.

Remove opinionated cursor styles on buttons

Restore `main` to package.json

Combine two same selectors

Remove `v1` references

Small copy change

Hi there, this is a possible alternative to: Improves [ ... ] improvements.
Feel free to ignore :)

All the best,

Michael

Fix spelling error in comment