Fixed a few typos with Docker/postgres upgrade instructions

docs/upgrading/index.rst

@@ -78,18 +78,18 @@ Thankfully, there is a Docker container available to automate this process. You
 can use the following snippet to upgrade your database in ``./postgres``,
 keeping a backup of the old version in ``./postgres-old``:
 
-.. parsed-literal::
+.. code-block:: shell
 
     # Replace "9.4" and "11" with the versions you are migrating between.
     export OLD_POSTGRES=9.4
     export NEW_POSTGRES=11
     docker-compose stop postgres
     docker run --rm \
-      -v `pwd`/data/postgres:/var/lib/postgresql/${OLD_POSTGRES}/data \
-      -v `pwd`/data/postgres-new:/var/lib/postgresql/${NEW_POSTGRES}/data \
+      -v $(pwd)/data/postgres:/var/lib/postgresql/${OLD_POSTGRES}/data \
+      -v $(pwd)/data/postgres-new:/var/lib/postgresql/${NEW_POSTGRES}/data \
       tianon/postgres-upgrade:${OLD_POSTGRES}-to-${NEW_POSTGRES}
     # Add back the access control rule that doesn't survive the upgrade
-    echo "host all all all trust" | sudo tee -a ./postgres-new/pg_hba.conf
+    echo "host all all all trust" | sudo tee -a ./data/postgres-new/pg_hba.conf
     # Swap over to the new database
     mv ./data/postgres ./data/postgres-old
     mv ./data/postgres-new ./data/postgres