Update Ubuntu Pro upgrade instructions in documentation

Author: genlin

support/azure/virtual-machines/linux/upgrade-canonical-ubuntu-18dot04-lts.md

@@ -22,7 +22,7 @@ Transitioning to the latest operating system, such as [Ubuntu 20.04 LTS](https:/
 
 ## Upgrade to Ubuntu Pro - Extended Security Maintenance until 2028
 
-Ubuntu Pro includes security patching for all Ubuntu packages because of Extended Security Maintenance (ESM) for infrastructure and applications and optional full-time (24 hours a day, seven days a week) telephone and ticket support. Ubuntu Pro 18.04 LTS will remain fully supported until April 2028. New VMs that run Ubuntu Pro can be deployed from the [Azure Marketplace](https://azuremarketplace.microsoft.com/marketplace/apps/canonical.0001-com-ubuntu-pro-bionic?tab=Overview). You can now upgrade your Ubuntu Server (version 16.04 or higher) VM to Ubuntu Pro by an [in-place upgrade](/azure/virtual-machines/workloads/canonical/ubuntu-pro-in-place-upgrade), or directly purchasing from [Canonical](https://ubuntu.com/pro). For more information about the end of standard support for Ubuntu 18.04 LTS, see [Ubuntu 18.04 LTS (Bionic Beaver) on Azure](https://ubuntu.com/18-04/azure). 
+Ubuntu Pro includes security patching for all Ubuntu packages because of Extended Security Maintenance (ESM) for infrastructure and applications and optional full-time (24 hours a day, seven days a week) telephone and ticket support. Ubuntu Pro 18.04 LTS will remain fully supported until April 2028. New VMs that run Ubuntu Pro can be deployed from the [Azure Marketplace](https://azuremarketplace.microsoft.com/marketplace/apps/canonical.0001-com-ubuntu-pro-bionic?tab=Overview). You can upgrade your Ubuntu Server (version 16.04 or higher) VM to Ubuntu Pro by an [in-place upgrade](/azure/virtual-machines/workloads/canonical/ubuntu-pro-in-place-upgrade), or directly purchase from [Canonical](https://ubuntu.com/pro). For more information about the end of standard support for Ubuntu 18.04 LTS, see [Ubuntu 18.04 LTS (Bionic Beaver) on Azure](https://ubuntu.com/18-04/azure). 
 
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