reST preview/error reporting when editing package description

[GoogleCodeExporter]

What steps will reproduce the problem?
1.If you edit package description in reStructuredText
2.and make an error, ...

What is the expected output? What do you see instead?
... you won't see this error. You markup will insted transform into plain text.

Please provide any additional information below.
It should be possible to use Trac-like format specificator as a first line and 
probably formatters can be borrowed too.

Original issue reported on code.google.com by [email protected] on 11 Sep 2011 at 7:41