Add pricing details for region pinning (multiple pages)

[BPKelley]

Added limits and pricing information for region pinning feature.

It's related to our rollout of this blog post tomorrow: https://github.com/ngrok-private/frontend/pull/2227

Also changing the actual pricing page: https://github.com/ngrok-private/frontend/pull/2248

[nijikokun]

Suggested change

	It will cost **$0.02 per active endpoint hour**, for each endpoint on a domain with region pinning enabled (as described above).
	* This is in addition to the existing rate for endpoints.
	* But you'll only be charged for region pinning when an endpoint is _actively_ sending or receiving traffic. If you have endpoints with pinning enabled, but they don't send/receive traffic, there are no associated costs from this feature.
	Region pinning will cost **$0.02 per active endpoint hour**, per endpoint on a pinned domain, in addition to the standard endpoint rate. You're only charged while an endpoint is actively handling traffic. Endpoints with pinning enabled that aren't serving traffic don't incur charges from this feature.

[BPKelley]

What do you think of this, or something similar? Does it address your clarity concerns here?

It's what I added to the blog post after feedback from both Sams:

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Region pinning is available on the Pay-as-you-Go plan. It will be charged at $0.02 per active endpoint hour, on top of the existing rate for endpoints. An endpoint is considered active if it receives any traffic in a given hour. Learn more on the pricing page.

If your pinned endpoints don't receive any traffic, you won't be charged for region pinning — no need to disable endpoints to save money. Your costs scale with your usage.

[S3Prototype]

I think niji's suggested change was for brevity, as the pricing explanation is a little technical and the less noise there the better. I like your new proposed change, so I will approve if you add it

[S3Prototype]

Thanks!