updating API docstring so that user can infer default value

Author: gregolsen

activesupport/lib/active_support/core_ext/date/calculations.rb

@@ -192,13 +192,13 @@ def end_of_week
   alias :sunday :end_of_week
   alias :at_end_of_week :end_of_week
 
-  # Returns a new Date/DateTime representing the start of the given day in the previous week (default is Monday).
+  # Returns a new Date/DateTime representing the start of the given day in the previous week (default is :monday).
   def prev_week(day = :monday)
     result = (self - 7).beginning_of_week + DAYS_INTO_WEEK[day]
     self.acts_like?(:time) ? result.change(:hour => 0) : result
   end
 
-  # Returns a new Date/DateTime representing the start of the given day in next week (default is Monday).
+  # Returns a new Date/DateTime representing the start of the given day in next week (default is :monday).
   def next_week(day = :monday)
     result = (self + 7).beginning_of_week + DAYS_INTO_WEEK[day]
     self.acts_like?(:time) ? result.change(:hour => 0) : result

activesupport/lib/active_support/core_ext/time/calculations.rb

@@ -176,12 +176,12 @@ def end_of_week
   end
   alias :at_end_of_week :end_of_week
 
-  # Returns a new Time representing the start of the given day in the previous week (default is Monday).
+  # Returns a new Time representing the start of the given day in the previous week (default is :monday).
   def prev_week(day = :monday)
     ago(1.week).beginning_of_week.since(DAYS_INTO_WEEK[day].day).change(:hour => 0)
   end
 
-  # Returns a new Time representing the start of the given day in next week (default is Monday).
+  # Returns a new Time representing the start of the given day in next week (default is :monday).
   def next_week(day = :monday)
     since(1.week).beginning_of_week.since(DAYS_INTO_WEEK[day].day).change(:hour => 0)
   end