Improve Drop Alt compatibility with VIA (#18041)

by slycedix

keyboards/massdrop/alt/keymaps/via/readme.md

@@ -0,0 +1,24 @@
+# VIA keymap for the Drop Alt Keyboard
+## *LED Modes:*
+Enables all RGB Matrix animation modes available in QMK, all of which are selectable through VIA or using the LED mode keys
+
+```c
+#define USB_LED_INDICATOR_ENABLE
+#define RGB_MATRIX_FRAMEBUFFER_EFFECTS 
+#define RGB_MATRIX_KEYPRESSES
+```
+
+## *User Keycodes:*
+All keyboard specific keycodes are defined in the user_keycodes space, allowing for them to be placed on your keyboard through VIA
+
+```c
+enum alt_keycodes {
+    U_T_AUTO = USER00,     //USB Extra Port Toggle Auto Detect / Always Active
+    U_T_AGCR,              //USB Toggle Automatic GCR control
+    DBG_TOG,               //DEBUG Toggle On / Off
+    DBG_MTRX,              //DEBUG Toggle Matrix Prints
+    DBG_KBD,               //DEBUG Toggle Keyboard Prints
+    DBG_MOU,               //DEBUG Toggle Mouse Prints
+    MD_BOOT,               //Restart into bootloader after hold timeout
+};
+```