These 3 release notes have had an element ID collision because both
the runtime changes and changes to the package "runtime" used the
same ID. Fix it by using a "pkg-" prefix for the runtime package.

Move the "runtime-again" ID from CL 129635 to a nearby <dt> element
so that existing links to https://golang.org/doc/go1.11#runtime-again
don't break.

Fixes #37036
Updates #36878

Change-Id: Ib68d93acfac802fd84c0a57485937e45dea2064a
Reviewed-on: https://go-review.googlesource.com/c/go/+/217797


Reviewed-by: Toshihiro Shiino <shiino.toshihiro@gmail.com>
Reviewed-by: Agniva De Sarker <agniva.quicksilver@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>