[gopls-release-branch.0.20] gopls/doc/release: fix (oddly) broken link

Change-Id: I6bd1f9950e7662eedd9f16bc46c12603858abf1c
Reviewed-on: https://go-review.googlesource.com/c/tools/+/691335
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Alan Donovan <adonovan@google.com>
(cherry picked from commit 9c64f689623d8e52b69092b2a1b71472d514a446)
Reviewed-on: https://go-review.googlesource.com/c/tools/+/691376
diff --git a/gopls/doc/release/v0.20.0.md b/gopls/doc/release/v0.20.0.md
index d045116..4dfc223 100644
--- a/gopls/doc/release/v0.20.0.md
+++ b/gopls/doc/release/v0.20.0.md
@@ -15,7 +15,7 @@
 ## Configuration changes
 
 This release enables by default the new persistent index of packages
-in the module cache. This was first attempted in [v0.19.0] but reverted
+in the module cache. This was first attempted in [v0.19](./v0.19.0.md) but reverted
 due to problems that have since been fixed.
 
 ## Web-based features