[eclipse-pmc] API change: Deprecate old file modification validator gett

[Michael Valenta <Michael_Valenta@xxxxxxxxxx>]

Earlier in 3.3 M6, we added the capability
to the validate-edit mechanism in Eclipse to allow headless clients to
indicate to the valildateEdit hook that prompting is OK if the hook has
access to a UI context (https://bugs.eclipse.org/bugs/show_bug.cgi?id=160905).
As part of this, we deprecated the IFileModificationValidator interface
and created an abstract FileModificationValidator class. However, we neglected
to deprecate the getter method on RepositoryProvider so clients are faced
with a none deprecated method that returns a deprecated interface. We are
seeking approval to deprecate this method and add a new method that returns
the new type.

Bug 176992 RepositoryProvider#getFileModificationValidator
returns deprecated interface
- https://bugs.eclipse.org/bugs/show_bug.cgi?id=176992

Benefits: Clients will better understand
that we have transitioned to a new validateEdit API

Risk: none

Michael