Remove curly braces around line count.

Summary:
I'm assuming they aren't meant to be there.

Old:
This file has a very large number of changes ({4,032} lines). Show File Contents

New:
This file has a very large number of changes (4,032 lines). Show File Contents

Test Plan:
Saved a 5000-line test file, diffed from /dev/null, uploaded diff to local
instance, viewed.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4462