* ext/tk/lib/tkextlib/tcllib/plotchart.rb: fix typo.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47057 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/tk/lib/tkextlib/tcllib/plotchart.rb

@@ -519,7 +519,7 @@ module Tk::Tcllib::Plotchart
   class Histogram < XYPlot
     TkCommandNames = [
       'canvas'.freeze,
-      '::Plotchart::createHistgram'.freeze
+      '::Plotchart::createHistogram'.freeze
     ].freeze
   end