AIP-122: lint for collection identifier segments being the plural form of the noun

[toumorokoshi]

AIP-122 states:

The collection identifier segments in a resource name must be the plural form of the noun used for the resource. (For example, a collection of Publisher resources is called publishers in the resource name.)

We should add a linter rule that validates this (there might be one, but I couldn't find one looking through 12* AIPs.

[toumorokoshi]

note: we can't really do this as there is guidance in the AIPs today that allow nested collections to have names that elide some of the name if it's already present in the parent:

https://google.aip.dev/122#collection-identifiers

If a resource name contains multiple levels of a hierarchy, and a parent collection's name is used as a prefix for the child resource's name, the child collection's name may omit the prefix.

So it's not possible to rely on this heuristic today.