Change selection behaviour

[MrMugame]

Ok, this is more of shot into the blind. It does a few things:

• It filters out all select.pointer events and fires an empty transaction on mouseup, which basically replicates obsidians behaviour for selections, meaning while you still hold down the mouse nothing happens and only when you let go, the view updates. This removes all the weird jitter/feed-back loops when selecting.
• You can now select part of a widgets code and part of the outside text and it will still render the widget code.
• Change all events for different kind of links to click as that is also the normal behaviour of <a>s. It just seems weird that sometimes stuff happens on mouseup and sometimes on mousedown (Maybe there is a reason, but I couldn't think of one). This also sometimes caused problems: When you for example select some text and end on a link with the cursor, that link triggered.
• Remove the drawSelection() extension. This maybe controversial and is definitely up for debate, but to me the default browser selection behaviour just seems more natural and we aren't using multi cursor/selection stuff anyways.

I'd love some feedback on this

[zefhemel]

Oh this is very interesting! Will require thorough testing though, so will get into this when I'm back

[zefhemel]

If this works as advertised it solves by primary and long lasting gripe with live preview in CodeMirror. Super exciting!