SVGs can have the same presentation attribute declared redundantly in
both the node attributes and `<style>` tag.
This wouldn't break anything, but we can shave off a few more bytes by
dropping the attribute in this case.
I also had some chores pending which were trivial individually, I opted
to incorporate them here as well.
* In JSDocs, use the nullable syntax as it's more concise and familiar
from TypeScript usage.
* discord → Discord (proper nouns should match capitalization)
* Use actions/checkout v4 instead of v2
node.parentNode will be removed in v3 along with JSAPI class wrapper on
each node.
Style manager uses it to find inherited styles. To workaround this
I collected all parents along with all styles. This constraints style
manager to work only with initial ast which should not be a problem as
each plagin execution is isolated.
Mocha doesn't have a lot of features provided by jest.
There is a great assertion library out of the box.
And the most cool feature is inline snapshots.
Mocha also hides errors which makes debugging a nightmare sometimes.
computeStyle(node) in isolation is quite slow utility because it
collects style elements across whole document, parses and sort them.
In this diff I splitted it into `collectStylesheet(root)` and
`computeStyle(stylesheet, node)` which are easy integrate with new
visitor plugin api.
Ref https://github.com/svg/svgo/issues/777
Currently a lot of optimisations are attributes specific and may be
broken because of inline or shared styles.
In this diff I'm trying to solve the problem with getComputedStyle
analog.
`computeStyle` collects attributes, shared css rules, inline styles
and inherited styles and checks whether they can be statically optimised
or left as deoptimisation.
