win32/registry.rb: make @@type2name an array

* ext/win32/lib/win32/registry.rb (@@type2name): make an array
  instead of a hash, keys are sequential numbers.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51574 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/win32/lib/win32/registry.rb

@@ -377,15 +377,16 @@ For detail, see the MSDN[http://msdn.microsoft.com/library/en-us/sysinfo/base/pr
       }
     end
 
-    @@type2name = { }
-    %w[
+    @@type2name = %w[
       REG_NONE REG_SZ REG_EXPAND_SZ REG_BINARY REG_DWORD
       REG_DWORD_BIG_ENDIAN REG_LINK REG_MULTI_SZ
       REG_RESOURCE_LIST REG_FULL_RESOURCE_DESCRIPTOR
       REG_RESOURCE_REQUIREMENTS_LIST REG_QWORD
-    ].each do |type|
-      @@type2name[Constants.const_get(type)] = type
-    end
+    ].inject([]) do |ary, type|
+      type.freeze
+      ary[Constants.const_get(type)] = type
+      ary
+    end.freeze
 
     #
     # Convert registry type value to readable string.