Fine-grained recompilation for numerical constants

#### Feature

Fine-grained recompilation for numerical constants.

#### Benefit

When developing, especially in creative contexts like games or visual demos, you often want to tweak a constant integer value and then rerun the application.

While live-reloading the value from within the application is superior, this is often hard to setup, and application specific. Furthermore, even if your application supports live-reloading, it may not support it for arbitrary numbers buried within an internal algorithm somewhere.

Having super quick compile times when only tweaking an integer would be a huge improvement to the development cycle.

#### Implementation

I'm not familiar with how cranelift works, but in the context of the recent stencil changes (https://www.reddit.com/r/rust/comments/zmqj0g/cranelift_progress_in_2022/), I imagine a way where the compiler could detect only an integer changed, and as fixed-size numericals take up constant space regardless of their value, patch in the new value either directly into the binary, or at least decreasing compile work.