Editor for large buffers of text

[nicoburns]

The current PlainEditor is great for editing small amounts of plain text. This makes it a good fit for text inputs in UIs (even multi-line text inputs). However it is backed by a single String which makes it very inefficient when editing large quanties of text. This makes it unsuitable for use cases like editing a text file.

We should create an editing abstraction that uses a Rope, Gap Buffer or similar that is suitable for these use cases.

[waywardmonkeys]

Unsurprisingly, I have thoughts on this. I will see if I can write them up within a day or two. There are needs for a text storage abstraction well beyond just editing.