Upcast context to reduce method instances generated by compiler

src/spectator/dsl/examples.cr

@@ -19,8 +19,8 @@ module Spectator::DSL
         ::Spectator::DSL::Builder.add_example(
           _spectator_example_name(\{{what}}),
           ::Spectator::Source.new(\{{block.filename}}, \{{block.line_number}}),
-          \{{@type.name}}.new
         ) { |example, context| context.as(\{{@type.name}}).\%test }
+          \{{@type.name}}.new.as(::Spectator::Context)
       end
     end