NPF Spec: Outdated maximum image count

[marcustyphoon]

https://github.com/tumblr/docs/blob/930050b56811a35ca75e71c7cb2330002ddc0573/npf-spec.md?plain=1#L1905-L1907

As of this Changes post, this is no longer true:

We’ve bumped the image limit in the beta post editor on web from 10 to 30. The post editor in the apps still has the 10 image limit due to some technical limitations we’re working on (you can still edit a post with 10+ images in the app, you just can’t add any more).

[sanmai]

Thanks for calling this out! We'll get this fixed up. 👌

[rtio]

We have updated the specs in ec08f10278aaa46862990c7516e92f77e57c68d9, thanks for that. @cyle or @sanmai could you close this issue?

[cyle]

sure thing, thanks!