Improve rendering of text-based file attachment thumbnails.
Review Request #5241 — Created Jan. 12, 2014 and submitted
Improve rendering of text-based file attachment thumbnails.
This applies syntax highlighting and decent rendering for text-based
file attachment thumbnails. Like the review UIs, these are now
syntax-highlighted. The text is also made small enough to show roughly 7
lines.
Tested with a few different types of text files.
