content/vscode-go: add redirect from long form URL

The canonical path for this blog post is the short path /vscode-go,
determined from the file name. This change adds a secondary longer
path that redirects to the canonical short one, so that both links
can work at the time the blog post is published.

Change-Id: I8f0edf44536d22ef2fd8693aa5c6e82947a8c7a6
Reviewed-on: https://go-review.googlesource.com/c/blog/+/237165
Reviewed-by: Rebecca Stambler <rstambler@golang.org>

content/vscode-go.article

diff --git a/content/vscode-go.article b/content/vscode-go.article
index e57ee8b..8ff833f 100644
--- a/content/vscode-go.article
+++ b/content/vscode-go.article
@@ -1,6 +1,7 @@
 # The VS Code Go extension joins the Go project
 09 Jun 2020
 Summary: Announcement of VS Code Go's move to the Go project.
+OldURL: /the-vs-code-go-extension-joins-the-go-project
 
 The Go & VS Code Teams