Add instructions for unintalling brew cask (#12861)

Author: sdwheeler

reference/docs-conceptual/install/alternate-install-methods.md

@@ -1,6 +1,6 @@
 ---
 description: Alternate ways to install PowerShell on non-Windows platforms.
-ms.date: 03/12/2026
+ms.date: 03/18/2026
 title: Alternate ways to install PowerShell
 ---
 # Alternate ways to install PowerShell
@@ -16,6 +16,10 @@ from the PowerShell Community or the operating system vendor. For support option
 Homebrew is the preferred package manager for macOS. If the `brew` command isn't found, you need to
 install Homebrew following [their instructions][12].
 
+> [!IMPORTANT]
+> The brew formula is maintained and supported by the Homebrew community. The brew formula builds
+> PowerShell from source code rather than installing a package built by Microsoft.
+
 ```bash
 /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
 ```
@@ -26,9 +30,16 @@ Once `brew` is installed, install PowerShell using the following command:
 brew install powershell
 ```
 
-> [!IMPORTANT]
-> The brew formula is maintained and supported by the Homebrew community. The brew formula builds
-> PowerShell from source code rather than installing a package built by Microsoft.
+If you previously installed PowerShell using the Homebrew cask, you must first uninstall the cask
+before you can successfully install using the Homebrew formula. Use the following commands to
+uninstall the cask:
+
+```sh
+# Uninstall the PowerShell cask instance
+brew uninstall --cask powershell
+# Uninstall the PowerShell Preview cask instance
+brew uninstall --cask powershell-preview
+```
 
 ### Update PowerShell 7
 

reference/docs-conceptual/toc.yml

@@ -213,7 +213,6 @@ items:
       - name: Glossary
         href: learn/glossary.md
   - name: What's New in PowerShell
-    expanded: true
     items:
       - name: Overview
         href: whats-new/overview.yml