Fix typo (whats → what's) (#947)

Author: lupino3

WSL/compare-versions.md

@@ -51,7 +51,7 @@ WSL 2 is only available in Windows 10, Version 1903, Build 18362 or higher. Chec
 > [!NOTE]
 > WSL 2 will work with [VMware 15.5.5+](https://blogs.vmware.com/workstation/2020/05/vmware-workstation-now-supports-hyper-v-mode.html) and [VirtualBox 6+](https://www.virtualbox.org/wiki/Changelog-6.0). Learn more in our [WSL 2 FAQs.](./wsl2-faq.md#will-i-be-able-to-run-wsl-2-and-other-3rd-party-virtualization-tools-such-as-vmware-or-virtualbox)
 
-## Whats new in WSL 2
+## What's new in WSL 2
 
 WSL 2 is a major overhaul of the underlying architecture and uses virtualization technology and a Linux kernel to enable new features. The primary goals of this update are to increase file system performance and add full system call compatibility.