* Message less confusing error to human
* Problem: Following error message is not helpful, because you have to reason
that '' actually means it's in the top-level, and the 'div' (not '</div>') is
an end tag
require "rexml/parsers/lightparser"
REXML::Parsers::LightParser.new('</div>').parse
#=> Missing end tag for '' (got 'div')
* Solution: add a special case in error handling just to change the error message
require "rexml/parsers/lightparser"
REXML::Parsers::LightParser.new('</div>').parse
#=> Unexpected top-level end tag (got 'div')
* Refactor by removing unnecessary `md` check
* Thanks @a_matsuda to review this at asakusa.rb!
https://github.com/ruby/rexml/commit/f6528d4477