Add note about Fn+F4 for the 14" model and 16" model

src/models/darp10/external-overview.md

@@ -80,6 +80,7 @@
 |![Fn-F1](./img/fn-f1.png)  |Fn+F1   |Toggle trackpad                    |
 |![Fn-F2](./img/fn-f2.png)  |Fn+F2   |Mic mute                           |
 |![Fn-F3](./img/fn-f3.png)  |Fn+F3   |Mute                               |
+|![Fn-F4](./img/fn-star.png)|Fn+F4   |Toggle keyboard backlight*         |
 |![Fn-F5](./img/fn-f5.png)  |Fn+F5   |Volume down                        |
 |![Fn-F6](./img/fn-f6.png)  |Fn+F6   |Volume up                          |
 |![Fn-F7](./img/fn-f7.png)  |Fn+F7   |Toggle displays                    |
@@ -89,8 +90,11 @@
 |![Fn-F11](./img/fn-f11.png)|Fn+F11  |Toggle airplane mode               |
 |![Fn-F12](./img/fn-f12.png)|Fn+F12  |Suspend                            |
 |![Fn-F12](./img/fn-dia.jpg)|Fn+`    |Play/Pause                         |
-|![Fn-*](./img/fn-star.png) |Fn+*    |Toggle keyboard backlight          |
+|![Fn-*](./img/fn-star.png) |Fn+*    |Toggle keyboard backlight*         |
 |![Fn-/](./img/fn-slash.png)|Fn+/    |Cycle keyboard brightness levels   |
 |![Fn--](./img/fn-minus.png)|Fn+-    |Decrease keyboard brightness       |
 |![Fn-+](./img/fn-plus.png) |Fn++    |Increase keyboard brightness       |
 |1                          |Fn+1    |Toggle fan between max/automatic   |
+
+* For the 14" version of the Darter Pro (darp10-b)
+* For the 16" version of the Darter Pro (darp10)