Update doc/api/buffer.md

Co-authored-by: Mohammed Keyvanzadeh <[email protected]>

Author: benjamingr

doc/api/buffer.md

@@ -3390,7 +3390,7 @@ console.log(buf.subarray(-5, -2).toString());
 added: v0.3.0
 changes:
   - version: REPLACEME
-    pr-url: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/41596
     description: The bug.slice method has been deprecated.
   - version:
     - v7.1.0