CHANGELOG.md: add release heading for v0.47.4

This is an automated CL which updates the CHANGELOG.md.

Change-Id: I5f0ee5071a96889344846990344735d7b48048d7
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/683415
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
kokoro-CI: kokoro <noreply+kokoro@google.com>
Reviewed-by: Hongxiang Jiang <hxjiang@golang.org>

CHANGELOG.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ec25a3e..148a752 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,15 @@
 ([Issue 3698](https://github.com/golang/vscode-go/issues/3698))
 * Addressed an issue that broke the `Debug Subtest At Cursor` command. ([Issue 3718](https://github.com/golang/vscode-go/issues/3718))
 
+## v0.47.4 (prerelease)
+
+Date: 2025-06-23
+
+This is the [pre-release version](https://code.visualstudio.com/api/working-with-extensions/publishing-extension#prerelease-extensions) of v0.48.
+
+**Full Changelog**: https://github.com/golang/vscode-go/compare/v0.46.0-rc.1...v0.47.4
+**Milestone**: https://github.com/golang/vscode-go/issues?q=milestone%3Av0.48.0
+
 ## v0.47.3 (prerelease)
 
 Date: 2025-06-05