Merge pull request opencontainers#317 from wking/no-pointers-for-slices-or-maps

style: Document recent Go-pointer exceptions

Author: crosbymichael

style.md

@@ -13,9 +13,14 @@ The redundancy reduction from removing the namespacing prefix is not useful enou
 ## Optional settings should have pointer Go types
 
 So we have a consistent way to identify unset values ([source][optional-pointer]).
+The exceptions are entries where the Go default for the type is a no-op in the spec, in which case `omitempty` is sufficient and no pointer is needed (sources [here][no-pointer-for-slices], [here][no-pointer-for-boolean], and [here][pointer-when-updates-require-changes]).
+
 
 [capabilities]: config-linux.md#capabilities
 [class-id]: config-linux.md#network
 [integer-over-hex]: https://github.com/opencontainers/specs/pull/267#discussion_r48360013
 [keep-prefix]: https://github.com/opencontainers/specs/pull/159#issuecomment-138728337
+[no-pointer-for-boolean]: https://github.com/opencontainers/specs/pull/290#discussion_r50296396
+[no-pointer-for-slices]: https://github.com/opencontainers/specs/pull/316/files#r50782982
 [optional-pointer]: https://github.com/opencontainers/specs/pull/233#discussion_r47829711
+[pointer-when-updates-require-changes]: https://github.com/opencontainers/specs/pull/317/files#r50932706