unlvtests: Fix typo in documentation (found by codespell)

Signed-off-by: Stefan Weil <sw@weilnetz.de>

unlvtests/README.md

@@ -88,7 +88,7 @@ or if you've already got a results file you want to change, you can do this:
 awk '$3 != 100 {print $0}'  results.txt  newresults.txt
 
 If you only want the last sections where things are broken down by
-word, you can add a sed commend, like this:
+word, you can add a sed command, like this:
 
 ocrevalutf8 wordacc ground.txt ocr.txt | sed '/^   Count   Missed %Right   $/,$ 
 !d' | awk '$3 != 100 {print $0}'  results.txt