Revert "filters/syntax-highlighting.sh: work around highlight --force bug"

This reverts commit f50be7fda0.

An update with the latest highlight landed in EPEL. This new version
doesn't have the --force bug, so the workaround can now be removed.

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>

filters/syntax-highlighting.sh

@@ -53,21 +53,4 @@ EXTENSION="${BASENAME##*.}"
 exec highlight --force -f -I -X -S $EXTENSION 2>/dev/null
 
 # This is for version 3
-#
-# On CentOS 6.2 (using highlight from EPEL), when highlight doesn't know about
-# an EXTENSION, it outputs a lua error and _no_ text, even when the --force
-# option is used.
-#
-# Also see the bug reports at:
-# http://sourceforge.net/tracker/?func=detail&aid=3490017&group_id=215618&atid=1034391
-# https://bugzilla.redhat.com/show_bug.cgi?id=795567
-#
-# This workaround can be removed when the bug is fixed upstream and the new
-# version is packaged in most distributions.
-#
-# The workaround is to set the extension to 'txt' (plain text) when highlight
-# exits with an error (doesn't know the format).
-#
-#echo "test" | highlight -f -I -O xhtml -S $EXTENSION &>/dev/null
-#[ ${?} -ne 0 ] && EXTENSION="txt"
 #exec highlight --force -f -I -O xhtml -S $EXTENSION 2>/dev/null