nil.to_d inconsistent (bigdecimal/util)

[kwerle]

nil.to_d should accept a single integer parameter optionally.

irb(main):007:0> RUBY_VERSION
=> "3.2.2"
irb(main):008:0> require 'bigdecimal/util'
=> true
irb(main):009:0> 0.0.to_d
=> 0.0
irb(main):010:0> 0.0.to_d(4)
=> 0.0
irb(main):012:0> nil.to_d
=> 0.0
irb(main):011:0> nil.to_d(4)
/usr/local/lib/ruby/3.2.0/bigdecimal/util.rb:182:in `to_d': wrong number of arguments (given 1, expected 0) (ArgumentError)                                     
        from (irb):11:in `<main>'                                               
        from /usr/local/lib/ruby/gems/3.2.0/gems/irb-1.6.2/exe/irb:11:in `<top (required)>'                                                                     
        from /usr/local/bin/irb:25:in `load'                                    
        from /usr/local/bin/irb:25:in `<main>'