Update MissingClassDocumentation.xq

The check was incorrect because the IsPrivate attribute has values False, not false.

rules/X++/MissingClassDocumentation.xq

@@ -10,7 +10,7 @@ declare function functx:trim ( $arg as xs:string? )  as xs:string
  
 <Diagnostics Category='Best practice' href='docs.microsoft.com/Socratex/MissingClassDocumentation' Version='1.0'>
 {
-  for $c in /(Class | Table | Form | Query)[@IsPrivate = "false" and functx:trim(@Comments) = ""]
+  for $c in /(Class | Table | Form | Query)[lower-case(@IsPrivate) = "false" and functx:trim(@Comments) = ""]
   return
     <Diagnostic>
       <Moniker>MissingClassDocumentation</Moniker>
@@ -24,4 +24,4 @@ declare function functx:trim ( $arg as xs:string? )  as xs:string
       <EndColumn>{string($c/@EndCol)}</EndColumn>
     </Diagnostic>  
 } 
-</Diagnostics>
+</Diagnostics>