self == other -> bool
[permalink][rdoc]数値として等しいか判定します。
Rational(2, 3) == Rational(2, 3) # => true
Rational(5) == 5 # => true
Rational(0) == 0.0 # => true
Rational('1/3') == 0.33 # => false
Rational('1/2') == '1/2' # => false