Yeah, started thinking about this as well. And I see 2 possible concepts:
a) It is a simple string with only IDE highlight suggestion and possibly automatic dedenting (but then the issue remains for variable capture)
b) It is t-string-like, but instead of interpolating, it captures variables that are used in mini-language. But in this case, what language is that? Is it limited to Python syntax?
(a) would be useful for code string inputs, such as implementations of multiline-lambda-via-string or sub-interpreter code input.
(b) is more purposed for mini string DSLs.