Add ANTITHESIS_MAX_NAME_LEN macro

[Bronek]

We have new users defining their own instrumentation points, and they have started using some very long messages, unaware that this may cause readability issues in report and also that these names are stuck "forever" (or until report history is truncated).

This change will enable us to enforce maximum assertion message (name) length.

I tested this with

#define ANTITHESIS_MAX_NAME_LEN 9

#include "antithesis_sdk.h"

int main() {
  using namespace antithesis;
  REACHABLE("Message 1", {{"a", 1}});
  ALWAYS_OR_UNREACHABLE(false, "Message 2");
  ALWAYS_GREATER_THAN(10, 20, "Hello");
  ALWAYS_SOME(NAMED_LIST(false), "Message");
  SOMETIMES_ALL(NAMED_LIST(false), "Msg");
  return 0;
}

I am not planning to bring this functionality to polyfills, as it would bring lots of extra assumptions into what polyfills are allowed (or not) to do.

[Bronek]

suggestions for better name here are welcome.

[wsx-antithesis]

We have new users defining their own instrumentation points, and they have started using some very long messages, unaware that this may cause readability issues in report and also that these names are stuck "forever" (or until report history is truncated).

I agree there are some conventions that one should follow in assertion messages to provide a good experience,
but we're not sure yet if imposing a user-configurable length limit is the way to go here.

This is still great feedback, and we'll definitely want to improve our documentation to help people follow good conventions in authoring assertions.
We just need to think a bit harder on whether to have some compile-time enforceable rules that works across all of our SDKs.

I'll keep this open for new ideas!