doc: update metadata for _transformState deprecation

It seems that the deprecated `_transformState` property was removed
at some point in the past but the deprecation metadata was not
updated accordingly.

PR-URL: #58530
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

Author: jasnell

doc/api/deprecations.md

@@ -2950,12 +2950,15 @@ upon `require('node:module').builtinModules`.
 
 <!-- YAML
 changes:
+  - version: v15.0.0
+    pr-url: https://github.com/nodejs/node/pull/33105
+    description: End-of-Life.
   - version: v14.5.0
     pr-url: https://github.com/nodejs/node/pull/33126
     description: Runtime deprecation.
 -->
 
-Type: Runtime
+Type: End-of-Life
 
 `Transform._transformState` will be removed in future versions where it is
 no longer required due to simplification of the implementation.