Update backup-and-restore.html.markerb

fix some errant backticks

Author: swilson-fly

postgres/managing/backup-and-restore.html.markerb

@@ -96,8 +96,8 @@ fly image show -a <postgres-app-name>
 MACHINE ID      REGISTRY                REPOSITORY      TAG     VERSION DIGEST                        LABELS                                                                          
 e286004f696700  registry-1.docker.io    flyio/postgres  14.6    v0.0.41 sha256:3c25db96357a78e827ca7d fly.app_role=postgres_clusterfly.pg-version=14.6-1.pgdg110+1fly.version=v0.0.41
 ```
-The values under the `REPOSITORY and `TAG columns are the image you'll use to restore the snapshot. 
-Legacy postgres images use the `flyio/postgres` repository, while new Postgres Flex images use the flyio/`postgres-flex` repository. In the above example, the machine is running a legacy `flyio/postgres:14.6` image.
+The values under the `REPOSITORY` and `TAG` columns reference the image you'll use to restore the snapshot. 
+Legacy postgres images use the `flyio/postgres` repository, while new Postgres Flex images use the `flyio/postgres-flex` repository. In the above example, the machine is running a legacy `flyio/postgres:14.6` image.
 
 ## Restoring from a snapshot