Output should display fields in the order given to -f

[rjw1]

While topfew-rs deals with being given fields in any order unlike topfew (timbray/topfew#8) it still displays them in numerical order instead of the order given.

 $  /Users/bob/.cargo/bin/tf -f 9,7 test/data/small
136  /ongoing/When/202x/2020/04/29/Leaving-Amazon 200
119  /ongoing/in-feed.xml 200
112  /ongoing/serif.css 200
112  /ongoing/ongoing.js 200
109  /ongoing/Feed.png 200
104  /ongoing/darkwater60.jpg 200
95  /ongoing/picInfo.xml?o=https://www.tbray.org/ongoing/When/202x/2020/04/29/Leaving-Amazon 200
89  /favicon.ico 200
28  408 "-"
12  /ongoing/picInfo.xml?o=https://old.tbray.org/ongoing/When/202x/2020/04/29/Leaving-Amazon 200

I would expect it to do the same as the equivalent in awk

 $  awk '{print $9 " " $7}' test/data/small | sort | uniq -c | sort -rn | head
 136 200 /ongoing/When/202x/2020/04/29/Leaving-Amazon
 119 200 /ongoing/in-feed.xml
 112 200 /ongoing/serif.css
 112 200 /ongoing/ongoing.js
 109 200 /ongoing/Feed.png
 104 200 /ongoing/darkwater60.jpg
  95 200 /ongoing/picInfo.xml?o=https://www.tbray.org/ongoing/When/202x/2020/04/29/Leaving-Amazon
  89 200 /favicon.ico
  28 "-" 408
  12 200 /ongoing/picInfo.xml?o=https://old.tbray.org/ongoing/When/202x/2020/04/29/Leaving-Amazon