Add 'radback' to dictionary with correction

Author: Flo3561

codespell_lib/data/dictionary.txt

@@ -47911,6 +47911,7 @@ racoon->raccoon
 racoons->raccoons
 ractise->practise
 radation->radiation
+radback->readback
 rade->read, raid,
 rademption->redemption
 rademptions->redemptions