Avoid defining Proc Contract

contracts tries to run given Procs since egonSchiele/contracts.ruby#251
and this sometimes causes RuntimeError

Author: amatsuda

Diff for: middleman-core/lib/middleman-core/application.rb

@@ -424,7 +424,6 @@ def use(middleware, *args, &block)
     #
     # @param [String] map Path to map
     # @return [void]
-    Contract String, Proc => Any
     def map(map, &block)
       @mappings << MapDescriptor.new(map, block)
     end

Diff for: middleman-core/lib/middleman-core/callback_manager.rb

@@ -32,7 +32,6 @@ def install_methods!(install_target, names)
       install_target.define_singleton_method(:subscribe_to_callbacks, &method(:subscribe))
     end
 
-    Contract Or[Symbol, ArrayOf[Symbol]], Proc => Any
     def add(keys, &block)
       immutable_keys = keys.is_a?(Symbol) ? keys : ::Hamster::Vector.new(keys)
 

Diff for: middleman-core/lib/middleman-core/core_extensions/collections.rb

@@ -65,7 +65,6 @@ def data_collector
           live_collector { |app, _| app.data }
         end
 
-        Contract Proc => LazyCollectorRoot
         def live_collector(&block)
           root = LazyCollectorRoot.new(self)