[ruby/reline] Drop Unicode.take_range's optional arg as it's never

used
(ruby/reline#528)

ruby/reline@428fed4a6a

Author: st0012

lib/reline/unicode.rb

@@ -192,8 +192,8 @@ def self.split_by_width(str, max_width, encoding = str.encoding)
   end
 
   # Take a chunk of a String cut by width with escape sequences.
-  def self.take_range(str, start_col, max_width, encoding = str.encoding)
-    chunk = String.new(encoding: encoding)
+  def self.take_range(str, start_col, max_width)
+    chunk = String.new(encoding: str.encoding)
     total_width = 0
     rest = str.encode(Encoding::UTF_8)
     in_zero_width = false