doc: use correct placeholder for policy docs

PR-URL: #25627
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>

Author: addaleax

Diff for: doc/api/cli.md

@@ -150,7 +150,7 @@ Enable experimental ES module support and caching modules.
 
 ### `--experimental-policy`
 <!-- YAML
-added: TODO
+added: REPLACEME
 -->
 
 Use the specified file as a security policy.

Diff for: doc/api/policy.md

@@ -1,6 +1,6 @@
 # Policies
 
-<!--introduced_in=TODO-->
+<!--introduced_in=REPLACEME-->
 <!-- type=misc -->
 
 > Stability: 1 - Experimental