RFR 9: JDK-8177076: jshell tool: usability of completion

[Jan Lahoda]

Hello,

I'd like to ask for a review of a patch that merges shift-tab and tab 
completions, and changes the fix shortcut to shift-tab:
Bug: https://bugs.openjdk.java.net/browse/JDK-8177076
Webrev: http://cr.openjdk.java.net/~jlahoda/8177076/webrev.00/

Any feedback is welcome,
      Jan