Semantic tokens make tokens types priority configurable

Since one token might be of several token types, but the result can only be one. It is more ideal for user to asign token type priorities to each of them if they desires.
For example: function and infix operators #3969.

Start by reading issue #3969 and locating the semantic-token handling entry point in the Haskell language server. Determine how a token with multiple types is currently resolved, then define and verify configurable priorities using the function and infix-operator example as the completion criterion.

Written by the indexing model from the issue text.