DOCSP-42405-enable-tlsUseSystemCA (#12386)

* DOCSP-42405-enable-tlsUseSystemCA

* add hyperlink

* removed default term

Author: oliviacaulfield

content/mongodb-shell/source/reference/options.txt

@@ -387,10 +387,11 @@ TLS Options
 
 .. option:: --tlsUseSystemCA
 
-   Allows ``mongosh`` to load TLS certificates available to the
-   operating system's certificate authority. Use this option if you want
-   to use TLS certificates already available to your operating system
-   without explicitly specifying those certificates to ``mongosh``.
+   Allows ``mongosh`` to load TLS certificates already available to the
+   operating system's certificate authority without explicitly specifying the
+   certificates to the shell. This behavior is always enabled and cannot be
+   turned off. :option:`--tlsUseSystemCA <--tlsUseSystemCA>` can still be set
+   for backward compatibility, but it has no effect.
 
 .. _mongosh-authentication-options: