Fix Relation#inspect failing due to private Results#results (#1733)

In v6.0, Results#results was made private, breaking Relation#inspect
which relied on delegating the `results` call through delegate_missing_to.
Since delegate_missing_to uses public_send, it cannot access private methods.

Fix by calling private_execute.first(11) directly instead of results.first(11).

Author: khasinski

lib/searchkick/relation.rb

@@ -22,7 +22,7 @@ def initialize(model, term = "*", **options)
 
     # same as Active Record
     def inspect
-      entries = results.first(11).map!(&:inspect)
+      entries = private_execute.first(11).map!(&:inspect)
       entries[10] = "..." if entries.size == 11
       "#<#{self.class.name} [#{entries.join(', ')}]>"
     end