REST spec for get-snapshots API missing pagination-related parameters

[DaveCTurner]

The REST spec for the get-snapshots API is missing several recently-added parameters about pagination:

https://github.com/elastic/elasticsearch/blob/b323e8e1db5ab0efda60c8b12e6658807fb20da3/rest-api-spec/src/main/resources/rest-api-spec/api/snapshot.get.json

Specifically, it now accepts the following unspecified parameters:

• after
• from_sort_value
• offset
• order
• size
• slm_policy_filter
• sort

[elasticmachine]

Pinging @elastic/es-distributed (Team:Distributed)