[Docs] Bootmagic Lite Caveat (#5069)

Document that using bootmagic lite resets the eeprom every time.

docs/feature_bootmagic.md

@@ -129,6 +129,8 @@ By default, these are set to 0 and 0, which is usually the "ESC" key on a majori
 
 And to trigger the bootloader, you hold this key down when plugging the keyboard in. Just the single key.
 
+!> Using bootmagic lite will **always reset** the EEPROM, so you will lose any settings that have been saved.
+
 ## Advanced Bootmagic Lite
 
 The `bootmagic_lite` function is defined weakly, so that you can replace this in your code, if you need.  A great example of this is the Zeal60 boards that have some additional handling needed.