_content/doc: fix broken link in go-get-install-deprecation.md
_content/doc: fix broken link in go-get-install-deprecation.md

Fixes golang/go#48046.

Change-Id: I237ffa34fb4e9273cb245066a7251a74186390c5
GitHub-Last-Rev: 2d49ff8b47878b3c049ff828fee3f1d9d1a4095e
GitHub-Pull-Request: golang/website#86
Reviewed-on: https://go-review.googlesource.com/c/website/+/346069
Reviewed-by: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@golang.org>
Reviewed-by: Jay Conrod <f3fadaedc813344da5ec13b41e26596889cc5baa@google.com>
Website-Publish: DO NOT USE <d181b7fea0ec87c86ba5a890ab716db52498e3ba@google.com>

golang/website,golang/website,golang/website,golang/website,golang/website,golang/website,golang/website