maxColorAttachments and maxFragmentOutputAttachments restrictions

ad #899

As we established, it doesnt relly matter at the moment, but:

1) For sanity, shouldn't `maxColorAttachments` be guaranteed to be greater or equal to `maxFragmentOutputAttachments`? It feels weird the shaders could use more outputs than the renderpass can ever load (though I can imagine the opposite).

2) `maxPerStageResources` footnote says it must be at least sum of stuff including `maxColorAttachments`. Shouldn't that conceptually say `maxFragmentOutputAttachments` instead?
All of the other limits in the sum are limits on Locations in shader interfaces, except the `maxColorAttachments`.