[eclipse-pmc] API Request: Change API for custom tooltips in viewers

[Boris Bokowski <Boris_Bokowski@xxxxxxxxxx>]

I would like to request two (breaking)
changes to an API that was added to JFace in 3.3M5.  The changes were
suggested by early adopters.

GOALS/BENEFITS:
The proposed changes will give clients more control about the widgets being
used in the custom tooltip, as well as enabling programmatic activation
of custom tooltips.

CORRESPONDING BUGS:
[JFace] JFace ToolTip class should support
manual activation - https://bugs.eclipse.org/bugs/show_bug.cgi?id=174844
[Viewers] Should be possible to override TooltipSupport - https://bugs.eclipse.org/bugs/show_bug.cgi?id=175098

RISKS:
Small since this API was only added in 3.3 M5.

PERFORMANCE IMPACTS:
none.

Thanks,
Boris