RFR 8145263: JShell API: Change the format of SourceCodeAnalysis#documentation

[ShinyaYoshida]

Hi Jan and Robert,
I'd like to propose changing the format of SourceCodeAnalysis#documentation.

The detail of the change is on the issue 8145263:
https://bugs.openjdk.java.net/browse/JDK-8145263
Please see it.

You can see the more example in the test of my patch.

Patch is here:
http://cr.openjdk.java.net/~shinyafox/kulla/8145263/webrev.00/

Please consider my proposal and review the patch.

Regards,
shinyafox(Shinya Yoshida)