Tweak wording of "beyond rust main function"

This is to make it clear that the unwind is going *past* it, not just
into it.

Author: ehuss

src/crates-and-source-files.md

@@ -126,8 +126,8 @@ r[crate.uncaught-foreign-unwinding]
 ### Uncaught foreign unwinding
 
 When a "foreign" unwind (e.g. an exception thrown from C++ code, or a `panic!`
-in Rust code compiled or linked with a different runtime) is not caught before
-reaching the `main` function, the process will be safely terminated. This may
+in Rust code compiled or linked with a different runtime) propagates beyond
+the `main` function, the process will be safely terminated. This may
 take the form of an abort, in which case it is not guaranteed that any `Drop`
 calls will be executed, and the error output may be less informative than if the
 runtime had been terminated by a "native" Rust `panic`.

src/panic.md

@@ -77,8 +77,8 @@ Unwinding with the wrong ABI is undefined behavior:
 
 r[panic.unwind.ffi.catch-foreign]
 Catching a foreign unwinding operation (such as a C++ exception) using
-[`std::panic::catch_unwind`], [`std::thread::JoinHandle::join`], or by letting it propagate all the way to a
-Rust `main()` function will have one of two behaviors, and it is unspecified
+[`std::panic::catch_unwind`], [`std::thread::JoinHandle::join`], or by letting it propagate beyond the
+Rust `main()` function or thread root will have one of two behaviors, and it is unspecified
 which will occur:
 * The process aborts.
 * The function returns a [`Result::Err`] containing an opaque type.