add pr-url

Author: Nitzan Uziely

doc/api/dgram.md

@@ -736,7 +736,7 @@ chained.
 added: v0.11.13
 changes:
   - version: REPLACEME
-    pr-url: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/37026
     description: AbortSignal support was added.
   - version: v11.4.0
     pr-url: https://github.com/nodejs/node/pull/23798