Merge pull request #31050 from y-yagi/remove_unused_methods

Remove unused `calculate_rounded_number` and `digit_count`

activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb

@@ -37,14 +37,6 @@ def convert
 
       private
 
-        def calculate_rounded_number(multiplier)
-          (number / BigDecimal.new(multiplier.to_f.to_s)).round * multiplier
-        end
-
-        def digit_count(number)
-          number.zero? ? 1 : (Math.log10(absolute_number(number)) + 1).floor
-        end
-
         def strip_insignificant_zeros
           options[:strip_insignificant_zeros]
         end