better way to verify install media

Hi,
Just downloading Alma Linux for a look-see and going through the verification process.

At https://wiki.almalinux.org/release-notes/8.5.html#installation-instructions
You suggest:
```
# calculate the downloaded ISO SHA256 checksum
$ sha256sum AlmaLinux-8.5-x86_64-boot.iso
65b3b4c17ce322081e2d743ee420b37b7213f4b14d2ec4f3c4f026d57aa148ec AlmaLinux-8.5-x86_64-boot.iso

# compare it with expected checksum, it should be the same
$ cat CHECKSUM | grep -E 'SHA256.*AlmaLinux-8.5-x86_64-boot.iso'
SHA256 (AlmaLinux-8.5-x86_64-boot.iso) = 65b3b4c17ce322081e2d743ee420b37b7213f4b14d2ec4f3c4f026d57aa148ec
```

Which is perfectly good :) but you could use:
```
$ sha256sum -c CHECKSUM --ignore-missing
AlmaLinux-8.5-x86_64-dvd.iso: OK
sha256sum: WARNING: 17 lines are improperly formatted
```

which is easier if you're a human :)