Add an upstream JSON fragment lexer
- Verified runtime improvement by comparing scripts/highlight.php on the one-line.json test case from D14273 with the new lexer enabled and commented out. Saw >10x local improvement. My local base runtime is also >10x better than the runtime from D14273. My laptop might be a little faster than whatever that hardware was, but this is probably mostly pygmentize improvements in my most recent version.
- Added a test case.
- Used the highlighter to produce reasonable-looking results:
Reviewers: chad, gd
Reviewed By: chad, gd
Maniphest Tasks: T9566
Differential Revision: https://secure.phabricator.com/D14292