Update about-fastpath.md

Document limited GA for 100Gbps FastPath Private Link

Author: mialdrid

articles/expressroute/about-fastpath.md

@@ -109,6 +109,13 @@ This preview is available for connections associated to ExpressRoute Direct circ
 > [!NOTE]
 > Private Link pricing will not apply to traffic sent over ExpressRoute FastPath during Public preview. For more information about pricing, check out the [Private Link pricing page](https://azure.microsoft.com/pricing/details/private-link/).
 > 
+## Limited General Availability (GA)
+FastPath Private Endpoint/Private Link support for 100Gbps ExpressRoute Direct connections is available for limited scenarios. To review the supported scenarios and enroll in the limited GA offering, please send an email **[email protected]** with the following information:
+- Azure subscription ID
+- Virtual Network(s) Azure Resource ID(s)
+- ExpressRoute Circuit(s) Azure Resource ID(s)
+- ExpressRoute Virtual Network Gateway Connection(s) Azure Resource ID(s)
+- Number of Private Endpoints/Private Link services deployed to the Virtual Network
 
 ## Next steps