[ruby/prism] Use common method to construct Location here

ruby/prism@588f41ed6b

Author: headius

prism/templates/lib/prism/serialize.rb.erb

@@ -437,11 +437,10 @@ module Prism
         tokens = [] #: Array[[Token, Integer]]
 
         while (type = TOKEN_TYPES.fetch(load_varuint))
-          start = load_varuint
-          length = load_varuint
+          location = load_location_object(false)
+
           lex_state = load_varuint
 
-          location = Location.new(@source, start, length)
           token = Token.new(@source, type, location.slice, location)
 
           tokens << [token, lex_state]