[editorial] Change fallback effective directive to connect-src (#614)

Author: antosart

index.bs

@@ -4358,7 +4358,15 @@ this algorithm returns normally if compilation is allowed, and throws a
       ::
         1. Return `connect-src`.
 
-  4.  Return null.
+      : "`report`"
+      ::
+        1. Return null.
+
+  4.  Return `connect-src`.
+
+  Note: The algorithm returns `connect-src` as a default fallback. This is
+  intended for new fetch destinations that are added and which don't explicitly
+  fall into one of the other categories.
 
   <h4 id="effective-directive-for-inline-check" algorithm>
     Get the effective directive for inline checks