csv.rb: fix typo

* lib/csv.rb (CSV#shift): fix typo.  [See GH-1160]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53183 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/csv.rb

@@ -1855,7 +1855,7 @@ class CSV
             csv.last << @col_sep
           end
         elsif part[0] == @quote_char
-          # If we are staring a new quoted column
+          # If we are starting a new quoted column
           if part[-1] != @quote_char || part.count(@quote_char) % 2 != 0
             # start an extended column
             csv             << part[1..-1]