doc: add YAML metadata for process.memoryUsage.rss

Refs: #34291

PR-URL: #36781
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

doc/api/process.md

@@ -1615,6 +1615,9 @@ informations about memory usage which can be slow depending on the
 program memory allocations.
 
 ## `process.memoryUsage.rss()`
+<!-- YAML
+added: REPLACEME
+-->
 
 * Returns: {integer}