Make it clear how to use swc-node

[jameshfisher]

swc-node is GREAT! BUT: I suspect you're losing many potential users because of the README.

Back in January, I wanted something to "run TypeScript with node". I was pointed to swc-node, and I looked at it, but dismissed because it wasn't clear what it did, or how to use it.

Then a few days ago, I was pointed to swc-node again. I looked at it again, and AGAIN I dismissed it because it wasn't clear what it did, or how to use it!

Here are some reasons I failed:

• The top-level README has lots of detail I don't care about. Support matrix right at the top, then detailed benchmarks. Could just say "fast and runs everywhere".
• Small links to sub-project READMEs are called "Detail", but those contain all the useful info! The "detail" is the support matrix and benchmarking.
• The name @swc-node/register means nothing to me. What is it registering? I didn't even visit that project README because it sounded irrelevant.
• @swc-node/register is listed last, but it's actually the user-facing project that I need to use.

Compare this with https://github.com/TypeStrong/ts-node. It says straight away what it is and how to use it.

[CLAassistant]

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