syntax-highlight: when the file has no extension, assume text

There are 2 situations:
1- empty extension: assuming text is better than highlight
   producing no output because of a missing argument.
2- no extension at all: assuming text is better than setting
   the extension to the filename, which is what now happens.

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