fix typo by @daveworth [fix GH-340]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41617 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

sample/freq.rb

@@ -1,5 +1,5 @@
 # word occurrence listing
-# usege: ruby freq.rb file..
+# usage: ruby freq.rb file..
 freq = Hash.new(0)
 while line = gets()
   line.scan(/\w+/) do |word|

sample/occur.rb

@@ -1,5 +1,5 @@
 # word occurrence listing
-# usege: ruby occur.rb file..
+# usage: ruby occur.rb file..
 freq = Hash.new(0)
 while line = gets()
   for word in line.split(/\W+/)

sample/occur2.rb

@@ -1,5 +1,5 @@
 # word occurrence listing
-# usege: ruby occur2.rb file..
+# usage: ruby occur2.rb file..
 freq = {}
 ARGF.each_line do |line|
   for word in line.split(/\W+/)