Fixes a typo in a comment.

# $(2) - Plain text output file

# $(3) - HTML/XML output file

# $(4) - File title

# $(5) - Directory to use.  Notice files are all $(4)/src.  Other

# $(5) - Directory to use.  Notice files are all $(5)/src.  Other

#		 directories in there will be used for scratch

# $(6) - Dependencies for the output files

#