Deleting a markdown block in the very first line

[mxstbr]

When I type a hash as the very first character, which converts the first line to a heading, I can never make that line leave heading mode again. Pressing backspace when there's no content left doesn't do anything. (the same thing is true for all other blocks too, like code)

Could we do something like: When the cursor is at the very first position in the editor and backspace is pressed revert that block to unstyled?

[mxstbr]

I fixed this in my fork, feel free to cherry-pick the commit to upstream: withspectrum#3 a4ef4ec