Too many values when unpacking a string literal

[lolpack]

Unpacking "abc" (length 3) into 2 targets should produce an error.

a, b = "abc"

Sandbox: Pyrefly

[yangdanny97]

same as the other one, we need to consider the runtime behavior for non-ascii characters like chinese or something, and make sure that our handling matches. i feel like this case also basically never happens in the wild since who would unpack a string literal like this