util: runtime deprecate util.isNull

PR-URL: #50488
Reviewed-By: Rafael Gonzaga <[email protected]>
Reviewed-By: Yagiz Nizipli <[email protected]>
Reviewed-By: Robert Nagy <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Ruben Bridgewater <[email protected]>
Reviewed-By: Joyee Cheung <[email protected]>

Author: marco-ippolito

doc/api/deprecations.md

@@ -1106,6 +1106,9 @@ The [`util.isFunction()`][] API is deprecated.
 
 <!-- YAML
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/50488
+    description: Runtime deprecation.
   - version:
     - v6.12.0
     - v4.8.6
@@ -1118,7 +1121,7 @@ changes:
     description: Documentation-only deprecation.
 -->
 
-Type: Documentation-only
+Type: Runtime
 
 The [`util.isNull()`][] API is deprecated.