Fix alignment in neat_list()

When neat_list() is printing information about a cipher suite that uses (EC)DH key exchange that was obtained using an old version of OpenSSL the rows are not properly aligned, since the key exchange input includes an unexpected trailing space. This commit fixes the problem by removing any trailing spaces from $kx.

testssl.sh

@@ -3331,6 +3331,7 @@ neat_list(){
      local -i i len
 
      kx="${3//Kx=/}"
+     kx="$(strip_trailing_space "$kx")"
      enc="${4//Enc=/}"
      # In two cases LibreSSL uses very long names for encryption algorithms
      # and doesn't include the number of bits.