Add macOS keybinding to lead paragraph

I wanted to provide the "search" keybinding for macOS users as well as Windows users.
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cc: @timwarner-msft

Author: timwarner-msft

articles/governance/policy/samples/built-in-policies.md

@@ -13,7 +13,7 @@ The name of each built-in links to the policy definition in the Azure portal. Us
 **Source** column to view the source on the
 [Azure Policy GitHub repo](https://github.com/Azure/azure-policy). The built-ins are grouped by the
 **category** property in **metadata**. To jump to a specific **category**, use the menu on the right
-side of the page. Otherwise, use <kbd>Ctrl</kbd>-<kbd>F</kbd> to use your browser's search feature.
+side of the page. Otherwise, use <kbd>Ctrl</kbd>-<kbd>F</kbd> (Windows) or <kbd>Cmd</kbd>-<kbd>F</kbd> (macOS) to use your browser's search feature.
 
 ## API for FHIR