fix: remove trailing backtick in verify-config for Loki 3.0 (#13640)

Co-authored-by: J Stickler <julie.stickler@grafana.com>

docs/sources/setup/upgrade/_index.md

@@ -69,7 +69,7 @@ If you would like to see if your existing configuration will work with Loki 3.0:
 1. In an empty directory on your computer, copy you configuration into a file named `loki-config.yaml`.
 1. Run this command from that directory: 
 ```bash
-docker run --rm -t -v "${PWD}":/config grafana/loki:3.0.0 -config.file=/config/loki-config.yaml -verify-config=true`
+docker run --rm -t -v "${PWD}":/config grafana/loki:3.0.0 -config.file=/config/loki-config.yaml -verify-config=true
 ```
 
 {{< admonition type="note" >}}