where can I find a clean copy of formatting.php v2.8

if I was stupid enough to make changes without backing it up first?

I tried to edit excerpt trimmer function (line 1704 to be exact) but now my site will not load at all. It says:

Parse error: parse error, expecting `’)” in /home/www/orchidexchange/wordpress2/wp-includes/formatting.php on line 321

Fatal error: Call to undefined function: untrailingslashit() in /home/www/orchidexchange/wordpress2/wp-includes/functions.php on line 365