[Haml] Make the - end error message better.

doc-src/HAML_CHANGELOG.md

@@ -13,6 +13,8 @@
   According to [this bug report](http://github.com/carlhuda/bundler/issues/issue/44),
   this should make Haml work better with Bundler.
 
+* Make the error message for `- end` a little more intuitive based on user feedback.
+
 ## 2.2.20
 
 [Tagged on GitHub](http://github.com/nex3/haml/commit/2.2.20).

lib/haml/precompiler.rb

@@ -245,11 +245,12 @@ END
         return start_haml_comment if text[1] == SILENT_COMMENT
 
         raise SyntaxError.new(<<END.rstrip, index) if text[1..-1].strip == "end"
-You don't need to use "- end" in Haml. Use indentation instead:
+You don't need to use "- end" in Haml. Un-indent to close a block:
 - if foo?
   %strong Foo!
 - else
   Not foo.
+%p This line is un-indented, so it isn't part of the "if" block
 END
 
         push_silent(text[1..-1], true)