Update README with TRIM usage instructions

Clarified instructions for enabling TRIM on SSDs.

README.md

@@ -37,7 +37,7 @@ #### What the script does:
     * Or you can tell the script which internal drive(s) DSM should read from.
 * Optionally disables Western Digital Device Analytics (aka WDDA) to prevent DSM showing a [warning for WD drives that are 3 years old](https://arstechnica.com/gadgets/2023/06/clearly-predatory-western-digital-sparks-panic-anger-for-age-shaming-hdds).
     * DSM 7.2.1 already has WDDA disabled.
-* Makes DSM allow you to enable TRIM on 3rd party SSDs in 2025+ models.
+* Makes DSM allow you to enable TRIM on 3rd party SSDs in 2025+ models. Don't use the `-f` or --force` option if you want to enable SSD TRIM.
 * Enables M2D20, M2D18, M2D17 and E10M20-T1 if present on Synology NAS that don't officially support them.
     * Newer NAS models may also need [Synology_enable_M2_card](https://github.com/007revad/Synology_enable_M2_card)
 * Checks that M.2 volume support is enabled (on models that have M.2 slots or PCIe slots).