Update navigation-has-label.md

Author: khiga8

docs/rules/accessibility/navigation-has-label.md

@@ -8,6 +8,10 @@ An accessible name ensures that one can distinguish between multiple navigation
 
 If the navigation area begins with a heading, use the heading to label the navigation element using the `aria-labelledby` attribute. If there is no heading, then you may set `aria-label`. Make sure to format the text the same way you would visual text (Related: [aria-label is well formatted](./aria-label-is-well-formatted.md)).
 
+### Assess whether a navigation landmark should be used
+
+This rule will flag all navigation landmarks that don't have an accessible name. However, in some instances, a navigation landmark may not be appropriate at all. While addressing this rule, please assess whether or not the instance you're looking at _should_ be a navigation landmark, and follow-up accordingly.
+
 ## Resources
 
 - [ARIA Landmarks Example](https://www.w3.org/WAI/ARIA/apg/example-index/landmarks/index.html)