Document comparison used with limits

[davidtwco]

rust-lang/rust#72540 makes sure that all comparisons against limits in the compiler are consistent, this should be documented in doc.rust-lang.org/reference/attributes/limits.html. rust-lang/rust#72540 should land before this is documented.

[Havvy]

Specifically, how has the comparison changed? Which sentences are now wrong?

[davidtwco]

Specifically, how has the comparison changed? Which sentences are now wrong?

No sentences are now wrong, but sentences could be added which describe that any values within the compiler are considered within the limit if they are less than or equal to the limit (previously this was inconsistent, sometimes less than, sometimes less than or equal).

[Havvy]

What about the code examples? Do they compile with the changed code?

[davidtwco]

What about the code examples? Do they compile with the changed code?

The first example still fails as expected (though I had to add semicolons after each of the macro expansions when running with rust-lang/rust#72540 locally - so that example will probably need updated at some point).

The second example failed with a different error than on the reference, but still due to recursion limits:

error[E0275]: overflow evaluating the requirement `fn(): std::marker::Freeze`
  |
  = help: consider adding a `#![recursion_limit="2"]` attribute to your crate (`foo2`)
  = note: required because it appears within the type `[closure@std::rt::lang_start::{{closure}}#0 0:fn()]`

The third example still fails as expected.