Auto merge of #115303 - matthiaskrgr:rollup-iohs8a5, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #109660 (Document that SystemTime does not count leap seconds)
 - #114238 (Fix implementation of `Duration::checked_div`)
 - #114512 (std/tests: disable ancillary tests on freebsd since the feature itsel…)
 - #114919 (style-guide: Add guidance for defining formatting for specific macros)
 - #115278 (tell people what to do when removing an error code)
 - #115280 (avoid triple-backtrace due to panic-during-cleanup)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

tests/fail/panic/double_panic.stderr

@@ -6,7 +6,6 @@ second
 stack backtrace:
 thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
 panic in a destructor during cleanup
-stack backtrace:
 thread caused non-unwinding panic. aborting.
 error: abnormal termination: the program aborted execution
   --> RUSTLIB/std/src/sys/PLATFORM/mod.rs:LL:CC
@@ -19,7 +18,7 @@ LL |     ABORT();
    = note: inside closure at RUSTLIB/std/src/panicking.rs:LL:CC
    = note: inside `std::sys_common::backtrace::__rust_end_short_backtrace::<[closure@std::panicking::begin_panic_handler::{closure#0}], !>` at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
    = note: inside `std::panicking::begin_panic_handler` at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside `core::panicking::panic_nounwind` at RUSTLIB/core/src/panicking.rs:LL:CC
+   = note: inside `core::panicking::panic_nounwind_nobacktrace` at RUSTLIB/core/src/panicking.rs:LL:CC
    = note: inside `core::panicking::panic_in_cleanup` at RUSTLIB/core/src/panicking.rs:LL:CC
 note: inside `main`
   --> $DIR/double_panic.rs:LL:CC