Refactor battery driver (#25550)

docs/features/battery.md

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+# Battery
+
+This feature provides the high level abstraction for sampling battery level.
+
+## Usage
+
+To use this driver, add the following to your `rules.mk`:
+
+```make
+BATTERY_ENABLE = yes
+```
+
+## Basic Configuration {#basic-configuration}
+
+Add the following to your `config.h`:
+
+|Define                    |Default |Description                                       |
+|--------------------------|--------|--------------------------------------------------|
+|`BATTERY_SAMPLE_INTERVAL` |`30000` |The time between battery samples in milliseconds. |
+
+## Driver Configuration {#driver-configuration}
+
+See the [Battery Driver](../drivers/battery) documentation for more information.
+
+## Functions
+
+### `uint8_t battery_get_percent(void)` {#api-battery-get-percent}
+
+Sample battery level.
+
+#### Return Value {#api-battery-get-percent-return}
+
+The battery percentage, in the range 0-100.
+
+## Callbacks
+
+### `void battery_percent_changed_user(uint8_t level)` {#api-battery-percent-changed-user}
+
+User hook called when battery level changed.
+
+### Arguments {#api-battery-percent-changed-user-arguments}
+
+ - `uint8_t level`  
+   The battery percentage, in the range 0-100.
+
+---
+
+### `void battery_percent_changed_kb(uint8_t level)` {#api-battery-percent-changed-kb}
+
+Keyboard hook called when battery level changed.
+
+### Arguments {#api-battery-percent-changed-kb-arguments}
+
+ - `uint8_t level`  
+   The battery percentage, in the range 0-100.