[basics] be more verbose about IO.lines. Noted by codyFendant++

src/basics.pod

@@ -194,7 +194,8 @@ X<block>
 C<for> produces a loop that runs the I<block> delimited by curly brackets and
 containing C<...> once for each item of the list, setting the variable C<$line>
 to the current value of each iteration. C<$file.lines> produces a list of the
-lines read from the file F<scores>.
+lines read from the file F<scores>, starting with the line where the previous
+calls to C<$file.get> left off, and going all the way to the end of the file.
 
 During the first iteration, C<$line> will contain the string C<Ana vs Dave |
 3:0>.  During the second, C<Charlie vs Beth | 3:1>, and so on.