Update the wording for the feature request issue template (elastic#57037

)

.github/ISSUE_TEMPLATE/feature-request.md

@@ -9,4 +9,13 @@ Please first search existing issues for the feature you are requesting;
 it may already exist, even as a closed issue.
 -->
 
-<!-- Describe the feature. -->
+<!--
+Describe the feature.
+
+Please give us as much context as possible about the feature. For example,
+you could include a story about a time when you wanted to use the feature,
+and also tell us what you had to do instead. The last part is helpful
+because it gives us an idea of how much harder your life is without the
+feature.
+
+-->