design/24543: fix broken links

These two proposal docs link to a common background doc, but the link
URL was wrong.

Change-Id: Ib4a5d4cc2ffd42d9b7dd0098695c5db1ad55a263
Reviewed-on: https://go-review.googlesource.com/c/proposal/+/219541
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

design/24543/conservative-inner-frame.md

diff --git a/design/24543/conservative-inner-frame.md b/design/24543/conservative-inner-frame.md
index 39e75f2..f478c6b 100644
--- a/design/24543/conservative-inner-frame.md
+++ b/design/24543/conservative-inner-frame.md
@@ -13,7 +13,7 @@
 We propose that the Go implementation switch to *non-cooperative*
 preemption.
 The background and rationale for this proposal are detailed in the
-[top-level proposal document](../20543-non-cooperative-preemption.md).
+[top-level proposal document](../24543-non-cooperative-preemption.md).
 
 This document details a specific approach to non-cooperative
 preemption that uses conservative GC techniques to find live pointers

design/24543/safe-points-everywhere.md

diff --git a/design/24543/safe-points-everywhere.md b/design/24543/safe-points-everywhere.md
index 329baf3..b0e200b 100644
--- a/design/24543/safe-points-everywhere.md
+++ b/design/24543/safe-points-everywhere.md
@@ -13,7 +13,7 @@
 We propose that the Go implementation switch to *non-cooperative*
 preemption.
 The background and rationale for this proposal are detailed in the
-[top-level proposal document](../20543-non-cooperative-preemption.md).
+[top-level proposal document](../24543-non-cooperative-preemption.md).
 
 This document details a specific approach to non-cooperative
 preemption based on constructing stack and register maps at