add defs to section headers [netlify-build]

Author: forstisabella

src/_includes/content/delivery-overview-discards.html

@@ -321,7 +321,7 @@
     <tr class="settingRow filtered-source">
       <td colspan="4" style="font-weight: bold; background-color:fafbff;font-size: 10px; text-transform: uppercase;"
         id="settingRow">
-        Filtered at Source</td>
+        Filtered at Source: Events that were discarded due to schema settings or <a href="/docs/protocols"> Protocols</a> Tracking Plans</td>
     </tr>
     <tr class="settingRow filtered-source" id="settingRow">
       <td>Common schema violation</td>
@@ -356,7 +356,7 @@
     <tr class="settingRow filtered-destination">
       <td colspan="4" style="font-weight: bold; background-color:fafbff;font-size: 10px; text-transform: uppercase;"
         id="settingRow">
-        Filtered at Destination</td>
+        Filtered at Destination: Events that were discarded due to Destination Filters, filtering in the Integrations object, or per source schema integration filters</td>
     </tr>
     <tr class="settingRow filtered-destination" id="settingRow">
       <td>Filtered by rules</td>
@@ -481,7 +481,7 @@
     <tr class="settingRow failed-delivery">
       <td colspan="4" style="font-weight: bold; background-color:fafbff;font-size: 10px; text-transform: uppercase;"
         id="settingRow">
-        Failed Delivery</td>
+        Failed Delivery: Events that have been discarded due to errors or unmet destination requirements</td>
     </tr>
     <tr class="settingRow failed-delivery" id="settingRow">
       <td>Invalid settings</td>