DOCSP-28171 Add troubleshooting on mongocli needing internet access by default (#811)

Co-authored-by: sarahsimpers <[email protected]>

Author: pierwill

source/troubleshooting.txt

@@ -122,3 +122,11 @@ HOMEDRIVE, HOMEPATH, or USERPROFILE are blank
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 This error might appear if {+mcli+} cannot access your home directory.
+
+Connection timeouts on internet-limited hosts
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+{+mcli+} checks for updates automatically.
+This can cause problems if you use {+mcli+} on systems with limited internet access.
+To prevent delays or timeouts, set the ``MCLI_SKIP_UPDATE_CHECK`` 
+:ref:`environment variable <mcli-env-var>` to ``true``.