func LookupPatchMetadataForStruct(t reflect.Type, jsonField string) ( elemType reflect.Type, patchStrategies []string, patchMergeKey string, e error)
Finds the patchStrategy and patchMergeKey struct tag fields on a given struct field given the struct type and the JSON name of the field. It returns field type, a slice of patch strategies, merge key and error. TODO: fix the returned errors to be introspectable.