doc: fix pr-url in repl.md

Now it points to the actual pr, not to /compare/.

PR-URL: #23359
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/repl.md

@@ -453,7 +453,7 @@ Returns `true` if `keyword` is a valid keyword, otherwise `false`.
 added: v0.1.91
 changes:
   - version: v10.0.0
-    pr-url: https://github.com/nodejs/node/pull/v10.0.0
+    pr-url: https://github.com/nodejs/node/pull/19187
     description: The `REPL_MAGIC_MODE` `replMode` was removed.
   - version: v5.8.0
     pr-url: https://github.com/nodejs/node/pull/5388