Update New-DlpComplianceRule.md

Author: aamalhot

exchange/exchange-ps/exchange/New-DlpComplianceRule.md

@@ -2491,7 +2491,9 @@ Accept wildcard characters: False
 ```
 
 ### -UnscannableDocumentExtensionIs
-{{ Fill UnscannableDocumentExtensionIs Description }}
+The UnscannableDocumentExtensionIs parameter specifies a condition for the rule that looks for the specified true file extension when the files are unscannable.
+
+You can specify multiple values separated by commas.
 
 ```yaml
 Type: MultiValuedProperty