Merge pull request #1059 from ruby/regexp-rbs

Let `Regexp.new` accept any `options` value

core/regexp.rbs

@@ -760,7 +760,7 @@ class Regexp
   #     r3 = Regexp.new(r2)              #=> /cat/i
   #     r4 = Regexp.new('dog', Regexp::EXTENDED | Regexp::IGNORECASE) #=> /dog/ix
   #
-  def initialize: (String string, ?Integer | nil | false options, ?String kcode) -> Object
+  def initialize: (String string, ?Integer | nil | false | top options, ?String kcode) -> Object
                 | (Regexp regexp) -> void
 
   # <!--