A large change again, mostly mechanical. There's a fair amount to clean up and that will come in the next commit.

This one is a much larger change but is mostly mechanical.

This change touches a lot of files but most of the changes are
mechanical. Essentially, this introduces a CompletionItemRules type as a
means to customize the behavior of a CompletionItem. This will
ultimately be the home of several methods that currently reside on
CompletionListProvider (such as IsCommitCharacter and
IsFilterCharacter), but only the SendEnterThroughToEditor method has
been moved in this change. Other methods will be moved in future
changes.

     Background:

     As discussed in the dev team all hands all code under the GitHub dotnet foundation is using a single process for contribution, API review, infrastructure and coding style. The idea is to present a unified view to our customer and give them a single story for contributing to any project under the dotnet foundation.

     https://github.com/dotnet/corefx/wiki/Contributing#c-coding-style

     The coding style transition is automated using a Roslyn based rewrite tool:

     https://github.com/dotnet/codeformatter

     This will be applied in stages across our developer tree. Right now the focus is on the Open directory as this is what is being presented on github. Code owners will be contacted before the transition happens.

     Note: this is a soft style requirement. There are no build errors that come from this change.
 (changeset 1408227)