[FIX] doc: explanation for pg_path

opw-2060249

closes odoo/odoo#36223

Signed-off-by: Xavier Morel (xmo) <xmo@odoo.com>

doc/reference/cmdline.rst

@@ -170,6 +170,12 @@ database
     when creating new databases from the database-management screens, use the
     specified `template database`_. Defaults to ``template1``.
 
+.. option:: --pg_path </path/to/postgresql/binaries>
+
+    Path to the PostgreSQL binaries that are used by the database manager to
+    dump and restore databases. You have to specify this option only if these
+    binaries are located in a non-standard directory.
+
 .. _reference/cmdline/server/internationalisation:
 
 Internationalisation