<Swing Dev> JDK 9 RFR of JDK-8076624: Fix missing doclint warnings in javax.swing.text

[joe darcy]

Hello,

Please review the change to address

     JDK-8076624: Fix missing doclint warnings in javax.swing.text
     http://cr.openjdk.java.net/~darcy/8076624.0/

(There were fewer context clues to fill in the missing javadoc compared 
to some recent fixes in the same vein.)

Thanks,

-Joe