Suggest adding a note as to the algorithm used for file checksums

[bryonbaker]

Is your feature request related to a problem? Please describe.
When I download the files and test the checksum I can't work out the algorithm used. I have tried sha256 and md5 with no match.

Describe the solution you'd like
If checksums.txt has a single line on top stating the algorithm used it would simplify the validation process.

Describe alternatives you've considered
Experimenting with lots of algorithms until it matches

Additional context
None.

[slimus]

Hello, @bryonbaker! We use a standard format for checksum files, we cannot change it. But I think we can change the file extension, to indicate checksum format: instead of checksums.txt we can use checksums.sha256. @derailed what do you think? Thanks!

[derailed]

Fixed #2153