Specified the file use in the print statement better.

Author: vermaseren

doc/manual/statements.tex

@@ -4286,7 +4286,9 @@ \section{print}
 
 \leftvitem{2cm}{{\tt<}filename{\tt>}}
 \rightvitem{14cm}{The results will be printed to the file. The {\tt<} and 
-{\tt>} are mandatory for this option.}
+{\tt>} are mandatory for this option.} This option can only be used in the 
+version that prints out individual terms, i.e. the version with the format 
+string.
 
 \leftvitem{1cm}{+f}
 \rightvitem{15cm}{Printing will be only to the log\index{log}