doc: migration-guide: 4.2: add migration guide entry for enable

- Add migration guide entry for enable->enable/disable function
- Add stepper_disable to stepper.rst

Signed-off-by: Jilay Pandya <jilay.pandya@outlook.com>

Author: jilaypandya

doc/hardware/peripherals/stepper.rst

@@ -14,6 +14,7 @@ Configure Stepper Driver
   and :c:func:`stepper_get_actual_position`.
 - Set **step interval** in nanoseconds between steps using :c:func:`stepper_set_microstep_interval`
 - **Enable** the stepper driver using :c:func:`stepper_enable`.
+- **Disable** the stepper driver using :c:func:`stepper_disable`.
 
 Control Stepper
 ===============

doc/releases/migration-guide-4.2.rst

@@ -136,6 +136,12 @@ Timer
   :kconfig:option:`CONFIG_NATIVE_POSIX_TIMER` has been deprecated in favor of
   :kconfig:option:`CONFIG_NATIVE_SIM_TIMER`, (:github:`86612`).
 
+Stepper
+=======
+
+  * Refactored the ``stepper_enable(const struct device * dev, bool enable)`` function to
+    :c:func:`stepper_enable` & :c:func:`stepper_disable`.
+
 Bluetooth
 *********