Feature request: Stop deletion at beginning of block

[brokosz]

Have you searched existing Github issues to see if someone has already requested this feature?
Yes

Is your feature request related to a problem? Please describe.
When holding in the delete key to delete a LOT of text in a block, it's easy to lose track of the cursor or get momentarily distracted and then all of a sudden you're deleting the contents of the previous block. If you have a LONG block and then several short blocks, it's easy to wipe it all out without noticing.

Describe the solution you'd like
When holding the delete key to text out of a block, it would be great that when the cursor reaches the beginning of the block it either stops and I have to let go of the key and re-engage to move to the previous block and keep deleting or if there was an interrupt (like a 0.7s pause) before the previous block begins deleting as well.

Describe alternatives you've considered
Not holding in delete? 😉 There's probably a behavior change (⌘ + A, del) I could do here, but the muscle memory is strong.

Additional context
Steps to recreate:

1. add several blocks to the buffer
2. go to the end of the bottom block
3. hold in the delete key and watch everything get wiped out

Thanks for all the great work on this app!

[brokosz]

Also I think this would very complimentary to block locking.