fireeth tools check merged-blocks doesn't print holes

[matthewdarwin]

fireeth tools check merged-blocks doesn't print holes

From indexer-firehose discussion:

✅ Range #0 - #999 999
✅ Range #1 000 000 - #1 999 999
✅ Range #2 000 000 - #2 999 999
✅ Range #3 000 000 - #3 999 999
✅ Range #4 000 000 - #4 999 999
✅ Range #5 000 000 - #5 999 999
✅ Range #6 000 000 - #6 999 999
✅ Range #7 500 100 - #8 000 099
✅ Range #8 000 100 - #9 000 099
✅ Range #9 000 100 - #10 000 099
✅ Range #10 000 100 - #11 000 099
✅ Range #11 500 100 - #12 000 199
✅ Range #13 000 100 - #13 000 399
✅ Range #13 000 400 - #14 000 399
✅ Range #15 000 100 - #15 071 299
✅ Range #15 750 100 - #16 071 599
✅ Range #17 000 100 - #17 071 699

Summary:
> 🆘 Holes found!

Was originally streamingfast/firehose-ethereum#70, moved to firehose-core.