Add UseCompatibleCmdlets rule documentation

Author: Kapil Borle

RuleDocumentation/README.md

@@ -45,4 +45,5 @@
 |[UseShouldProcessForStateChangingFunctions](./UseShouldProcessForStateChangingFunctions.md) | Warning|
 |[UseSingularNouns](./UseSingularNouns.md) | Warning|
 |[UseStandardDSCFunctionsInResource](./UseStandardDSCFunctionsInResource.md) | Error |
-|[UseToExportFieldsInManifest](./UseToExportFieldsInManifest.md) | Warning|
+|[UseToExportFieldsInManifest](./UseToExportFieldsInManifest.md) | Warning|
+|[UseCompatibleCmdlets](./UseCompatibleCmdlets.md) | Warning|

RuleDocumentation/UseCompatibleCmdlets.md

@@ -2,16 +2,15 @@
 **Severity Level: Warning**
 
 ## Description
-
-## How to Fix
-
-## Example
-### Wrong：
+This rule flags cmdlets that are not available in a given Edition/Version of PowerShell on a given Operating System. It works by comparing a cmdlet against a set of whitelists which ship with PSScriptAnalyzer. They can be found at `/path/to/PSScriptAnalyzerModule/Settings`. These files are of the form, `PSEDITION-PSVERSION-OS.json` where `PSEDITION` can be either `core` or `desktop`, `OS` can be either `windows`, `linux` or `osx`, and `version` is the PowerShell version. To enable the rule to check if your script is compatible on PowerShell Core on windows, put the following your settings file:
 ```PowerShell
-
+@{
+    'Rules' = @{
+        'PSUseCompatibleCmdlets' = @{
+            'compatibility' = @("core-6.0.0-alpha-windows")
+        }
+    }
+}
 ```
 
-### Correct:
-```PowerShell
-
-```
+The parameter `compatibility` is a list that contain any of the following `{core-6.0.0-alpha-windows, core-6.0.0-alpha-linux, core-6.0.0-alpha-osx}`.