Can provide a GHC.Runtime.Eval.getDocsBatch

Motivation

HLS for GHC.Runtime.Eval API implements some additions.

getDocsBatch - a batch retrieval form of getDocs, which optimization I do in the https://github.com/haskell/haskell-language-server/pull/2371/files.

It essentially takes a list of identifiers to look up. Then groups identifiers requested by modules where they are at, and then loads & opens each module interface once & retrieves all requested identifiers in that module at once & then goes to process interface of another requested module.

Proposal

It may have value as an API ability, to optimize mass retrieval of information.