RFR: 8046485: Add missing @since tag under javax.swing.*

[Henry Jen]

Hi,

Please review a trivial webrev that provides missing @since tag for 
elements under javax.swing,

Essentially it's simply add @since 1.2 for all 
classes/interfaces/exception that are missing @since tag, as JDK 1.2 
package.html has @since tag but was removed in 1.3.

The @since tag is added to *.java instead of package.html so that we can 
have javac report javadoc via 
javax.lang.model.util.Elements.getDocComment(Element c).

http://cr.openjdk.java.net/~henryjen/jdk9/8046485/0/webrev/

Cheers,
Henry