…tring literals.

Pros:

* Prevents mistaken usage of dynamically allocated strings.
* Lets us use static constant memory for the source location data.
* Avoids generating unnecessary writes to source location data whenever starting a zone.
* Matches other Zig Tracy bindings such as the one inside the Zig compiler.

Cons:

* Breaking API change.
* Technically you are allowed to pass non-string literals to these functions, and you might want to if you are dynamically loading code/data containing your strings, or promise to keep your strings allocated until program exit. We could export the raw C API to cover more niche use-cases such as these though.