CHANGELOG.md: add release heading for v0.46.1

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

Change-Id: I09564d6f2261b837e803a77d82254de3c8ba3f82
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/654420
Auto-Submit: Gopher Robot <[email protected]>
Reviewed-by: Alan Donovan <[email protected]>
kokoro-CI: kokoro <[email protected]>
Reviewed-by: Hongxiang Jiang <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

Author: gopherbot

CHANGELOG.md

@@ -5,6 +5,13 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/).
 
 ## Unreleased
 
+## v0.46.1
+
+Date: 2025-03-04
+
+**Full Changelog**: https://github.com/golang/vscode-go/compare/v0.46.1...v0.46.1
+**Milestone**: https://github.com/golang/vscode-go/issues?q=milestone%3Av0.46.1
+
 ## v0.47.1 (prerelease)
 
 Date: 2025-03-04