Update Set-CsMeetingConfiguration.md

I have added the following to the description for CustomFooterText: Multiple lines are supported using the Enter key. This request came via Content Idea 92143. Thanks!

Author: Cloud-Writer

skype/skype-ps/skype/Set-CsMeetingConfiguration.md

@@ -311,7 +311,7 @@ Accept wildcard characters: False
 ```
 
 ### -CustomFooterText
-Text to be used on custom meeting invitations.
+Text to be used on custom meeting invitations. Multiple lines are supported using the Enter key.
 
 ```yaml
 Type: String