Add Haskell and Objective-C syntax highlighting to paste

Summary:
Pygments already supports Haskell and Objective-C syntax
highlighting, but the default in Phabricator excluded them from the
dropdown for the paste tool.

This adds Haskell and Objective-C to the default list of languages.

Test Plan:
Started up Phabricator sandbox instance, confirmed Haskell
and Objective-C worked in paste app.

Reviewers: vrana, epriestley

Reviewed By: vrana

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D3510