Adds support for dev builds of TS

[orta]

Adds the basic support we'd need on the playground side for hooking into a built copy of the compiler.

[github-actions]

	Messages
📖	Deployed to a PR branch - playground tsconfig old handbook

Got false positives?

Make changes to the global settings spellcheck.json in /artsy/peril-settings.

Typos for README.md

Line	Typo
6	work by [Artem Tyurin](https://github.com/ag
6	work by [Artem Tyurin](https://github.com/agentcoop
14	- The sidebar plugin infrastructure for showing JS
25	- #code/PRA - A base64 and zipped version of the cod
26	- #src/The%20code - URLEncoded way to have the code for the
31	is loaded, show the examples popover
32	is loaded, show the examples popover
36	edge.net/indexes/pre-releases.json) [json](https://typescript.az
45	re is an installed playground plugin of that name, and if not offe

Generated by 🚫 dangerJS against 2d3cfc7

[orta]

"4.0.0-dev"

[orta]

This isn't 100% complete, because this setting needs to be propagated to the d.ts lookup in twoslash, but it's good enough for now