Swift: Add comment.

Author: geoffw0

swift/ql/lib/codeql/swift/frameworks/StandardLibrary/CustomUrlSchemes.qll

@@ -3,6 +3,10 @@ private import codeql.swift.dataflow.DataFlow
 private import codeql.swift.dataflow.ExternalFlow
 private import codeql.swift.dataflow.FlowSources
 
+/**
+ * A model for custom URL remote flow sources. iOS apps can receive arbitrary
+ * URLs from other apps in these functions if they register a custom URL scheme.
+ */
 private class CustomUrlRemoteFlowSource extends SourceModelCsv {
   override predicate row(string row) {
     row =