bug#46802: grep (GNU grep) 3.6 RexEx range reversed.

[Georgi K.]

 Dear Grep team,  
  
  My installation of grep thinks [a-Z] is a valid range, while [A-z] is not.  
  OS:  ArcoLinux  
  Kernel Version:
5.11.1-zen1-1-zen  
  Grep Version:
  grep (GNU grep) 3.6  
  Shell Version:
GNU bash, version 5.1.4(1)-release (x86_64-pc-linux-gnu)
  
  Locale:
en_US.utf8  
  Steps to reproduce:  
  $ echo "test" | grep -E "[a-Z]"
test
  
 $ echo "test" | grep -E "[A-z]"
 grep: Invalid range end  
  Please, let me know if I can produce some debug log for you.  
  
  Best,  
  George