Improve readability of docs by using code tag [ci skip]

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

@@ -5,7 +5,7 @@ class Object
   #   characters = ["Konata", "Kagami", "Tsukasa"]
   #   "Konata".in?(characters) # => true
   #
-  # This will throw an ArgumentError if the argument doesn't respond
+  # This will throw an +ArgumentError+ if the argument doesn't respond
   # to +#include?+.
   def in?(another_object)
     another_object.include?(self)
@@ -18,7 +18,7 @@ def in?(another_object)
   #
   #   params[:bucket_type].presence_in %w( project calendar )
   #
-  # This will throw an ArgumentError if the argument doesn't respond to +#include?+.
+  # This will throw an +ArgumentError+ if the argument doesn't respond to +#include?+.
   #
   # @return [Object]
   def presence_in(another_object)

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

@@ -94,7 +94,7 @@ class Object
   # :call-seq:
   #   try!(*a, &b)
   #
-  # Same as #try, but raises a NoMethodError exception if the receiver is
+  # Same as #try, but raises a +NoMethodError+ exception if the receiver is
   # not +nil+ and does not implement the tried method.
   #
   #   "a".try!(:upcase) # => "A"