rremove upstream note on vol_state_process

CONTRIBUTING.md

@@ -36,28 +36,3 @@ View logs over the serial port with
 
 Create a new release by moving the "Unreleased" section in [`CHANGELOG.md`](./CHANGELOG.md) to a new version.
 Once pushed the [`main.yml`](./.github/workflows/main.yml) workflow will create a new release.
-
-## notes
-
-> **NOTE**: upstream wrote this; leaving until I better understand
-
-This is the core function:
-
-```c
-void vol_state_process(uint32_t ambient_db) {
-    int volume = app_bt_stream_local_volume_get();
-     TRACE(2,"ambient db: %d volume: %d ", ambient_db, volume);
-
-     if((ambient_db < 52) && (volume > 10)) {
-         app_bt_volumedown();
-     }
-     else if((ambient_db > 60) && (volume < 13)) {
-         app_bt_volumeup();
-     }
-     else if((ambient_db > 72) && (volume < 15)) {
-         app_bt_volumeup();
-     }
-}
-```
-
-If you need key switch control, set a global variable to control whether to call this function where `vol_state_process((uint32_t)db_sum);` is called.