RFR [9] 8078622: remove tidy warnings from JPDA docs

[alexander stepanov]

Hello,

Could you please review the following fix
http://cr.openjdk.java.net/~avstepan/8078622/webrev.00/

for
https://bugs.openjdk.java.net/browse/JDK-8078622

Just some HTML cleanup for docs.

Thanks,
Alexander