Overly-strict description for single-line Javadoc at the Java Style Guide

originally reported by Googlers ( @ekuefler ) at https://github.com/checkstyle/checkstyle/pull/1545 see all details there.

it is proved by report on Guava that style guide mean that inline tokes should be allowed in single line javadocs, but we need to change guide first to let Checkstyle change configuration. Checkstyle team need to be sure that we are right in interpretation of style guide.

Side note: detailed report on how Checkstyle cover all rules of Google Style guide could be found there - http://checkstyle.sourceforge.net/google_style.html