doc: write various runtime-related release notes

doc: write various runtime-related release notes

This includes release notes for several small runtime changes, including
runtime/trace and runtime package changes.

For #58645.

Change-Id: I3e9c804da1bb6b385088e16a20d9576c11098021
Reviewed-on: https://go-review.googlesource.com/c/go/+/497095
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ansiwen <ansiwen@gmail.com>
Reviewed-by: Felix Geisendörfer <felix.geisendoerfer@datadoghq.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>