Rename Liquid::Registers @registers to @changes

since it doesn't represent all the registers

lib/liquid/registers.rb

@@ -5,31 +5,31 @@ module Liquid
     attr_reader :static
 
     def initialize(registers = {})
-      @static    = registers.is_a?(Registers) ? registers.static : registers
-      @registers = {}
+      @static = registers.is_a?(Registers) ? registers.static : registers
+      @changes = {}
     end
 
     def []=(key, value)
-      @registers[key] = value
+      @changes[key] = value
     end
 
     def [](key)
-      if @registers.key?(key)
-        @registers[key]
+      if @changes.key?(key)
+        @changes[key]
       else
         @static[key]
       end
     end
 
     def delete(key)
-      @registers.delete(key)
+      @changes.delete(key)
     end
 
     UNDEFINED = Object.new
 
     def fetch(key, default = UNDEFINED, &block)
-      if @registers.key?(key)
-        @registers.fetch(key)
+      if @changes.key?(key)
+        @changes.fetch(key)
       elsif default != UNDEFINED
         if block_given?
           @static.fetch(key, &block)
@@ -42,7 +42,7 @@ module Liquid
     end
 
     def key?(key)
-      @registers.key?(key) || @static.key?(key)
+      @changes.key?(key) || @static.key?(key)
     end
   end