Use Module#include rather than prepend since we don't need prepend semantics here and include leads to faster method lookups.

Author: nirvdrum

activesupport/lib/active_support/core_ext/numeric/conversions.rb

@@ -140,6 +140,6 @@ def to_fs(format = nil, options = nil)
   end
 end
 
-Integer.prepend ActiveSupport::NumericWithFormat
-Float.prepend ActiveSupport::NumericWithFormat
-BigDecimal.prepend ActiveSupport::NumericWithFormat
+Integer.include ActiveSupport::NumericWithFormat
+Float.include ActiveSupport::NumericWithFormat
+BigDecimal.include ActiveSupport::NumericWithFormat

activesupport/lib/active_support/core_ext/object/json.rb

@@ -46,7 +46,7 @@ def to_json(options = nil)
 end
 
 [Enumerable, Object, Array, FalseClass, Float, Hash, Integer, NilClass, String, TrueClass].reverse_each do |klass|
-  klass.prepend(ActiveSupport::ToJsonWithActiveSupportEncoder)
+  klass.include(ActiveSupport::ToJsonWithActiveSupportEncoder)
 end
 
 class Module