Update doc/guides/investigating_native_memory_leak.md

Co-Authored-By: Denys Otrishko <9109612+lundibundi@users.noreply.github.com>
nodejs · mhdawson · Jan 24, 2020 · Jan 27, 2020 · Jan 27, 2020 · Jan 27, 2020
commit eafd4287c7a32a7a2f12c5475d9d8827bb883e73
diff --git a/doc/guides/investigating_native_memory_leak.md b/doc/guides/investigating_native_memory_leak.md
@@ -331,6 +331,11 @@ results in the addons being compiled with the debug option.
 If the native addon contains pre-built binaries you will need to force
 a rebuild.
 
+```console
+npm install --debug
+npm rebuild
+```
+
 The next step is to run valgrind after the rebuild. This time the information
 for the leaking location includes the name of the source file and the
 line number: