Document skip-vanilla-damage-tick-when-shield-blocked

config-specs/paper/paper-global.yml

@@ -407,6 +407,13 @@ unsupported-settings:
     description: >-
       Whether to allow duplication of TNT, carpets, and rails. This does not
       control sand duplication
+  skip-vanilla-damage-tick-when-shield-blocked:
+    default: "false"
+    description: >-
+      Whether the server should skip damage ticks when entities are blocking damage
+      via a shield. While vanilla does process a damage tick, this was a long standing
+      bug in paper. Enabling this option means that the damage tick will be skipped, which
+      may result in rapid damage on shields due to the missing invulnerability.
   perform-username-validation:
     default: "true"
     description: >-