Fix Encoder documentation (#4861)

docs/feature_encoders.md

@@ -32,15 +32,19 @@ The callback functions can be inserted into your `<keyboard>.c`:
 or `keymap.c`:
 
     void encoder_update_user(uint8_t index, bool clockwise) {
-        if (index == 0) {
-            if (clockwise) {
-                register_code(KC_PGDN);
-                unregister_code(KC_PGDN);
-            } else {
-                register_code(KC_PGUP);
-                unregister_code(KC_PGUP);
-            }
+      if (index == 0) { /* First encoder */
+        if (clockwise) {
+          tap_code(KC_PGDN);
+        } else {
+          tap_code(KC_PGUP);
         }
+      } else if (index == 2) {
+        if (clockwise) {
+          tap_code(KC_UP);
+        } else {
+          tap_code(KC_DOWN);
+        }
+      }
     }
 
 ## Hardware

docs/features.md

@@ -11,6 +11,7 @@ QMK has a staggering number of features for building your keyboard. It can take
 * [Combos](feature_combo.md) - Custom actions for multiple key holds.
 * [Command](feature_command.md) - Runtime version of bootmagic (Formerly known as "Magic").
 * [Dynamic Macros](feature_dynamic_macros.md) - Record and playback macros from the keyboard itself.
+* [Encoders](feature_encoders.md) - Rotary encoders! 
 * [Grave Escape](feature_grave_esc.md) - Lets you use a single key for Esc and Grave. 
 * [HD44780 LCD Display](feature_hd44780.md) - Support for LCD character displays using the HD44780 standard.
 * [Key Lock](feature_key_lock.md) - Lock a key in the "down" state.