Update visualize results (#3067)

closes #2619 

Updated file:
https://qiskit.github.io/documentation/pr-3067/docs/guides/visualize-results

---------

Co-authored-by: Frank Harkins <[email protected]>
Co-authored-by: Jessie Yu <[email protected]>

Author: 3 people

docs/guides/local-testing-mode.ipynb

@@ -46,7 +46,8 @@
     "\n",
     "\n",
     "<Admonition type=\"note\" title=\"Notes\">\n",
-    "You can specify all Qiskit Runtime options in local testing mode.  However, all options except shots are ignored when run on a local simulator.\n",
+    "- You can specify all Qiskit Runtime options in local testing mode.  However, all options except shots are ignored when run on a local simulator.\n",
+    "- It is recommended that you install Qiskit Aer before using fake backends or Aer simulators by running `pip install qiskit-aer`. The fake backends use Aer simulators under the cover if available, to take advantage of their performance.\n",
     "</Admonition>\n",
     "\n",
     "\n",