docs/nRF52840-DK: Review comments fix

* Fixed review comments, fixes issue
  https://git.ostc-eu.org/OSTC/OHOS/meta-ohos/-/issues/62

.

Signed-off-by: Arul Kumaran <arulkumaran.devarajan@huawei.com>

docs/hardware-support/boards/nRF52840-DK.rst

@@ -5,7 +5,7 @@
 .. _SupportedBoardnRF52840DK:
 
 nRF52840 DK
-############
+###########
 
 .. contents::
    :depth: 3
@@ -13,9 +13,10 @@ nRF52840 DK
 Overview
 ********
 
-The nRF52840 DK is a low-cost single-board development kit that uses the nRF52840
-multi-protocol SoC to develop Bluetooth® 5, Bluetooth mesh, Thread, Zigbee, ANT, IEEE 802.15.4, and 2.4 GHz
-proprietary applications. It also supports development on the nRF52811 SoC.
+The nRF52840 DK is a low-cost single-board development kit that uses the
+nRF52840 multi-protocol SoC to develop Bluetooth® 5, Bluetooth mesh, Thread,
+Zigbee, ANT, IEEE 802.15.4, and 2.4 GHz proprietary applications. 
+It also supports development on the nRF52811 SoC.
 
 Hardware
 ********
@@ -45,7 +46,8 @@ All Scenarios OS Zephyr flavour is based on Zephyr kernel.
 
    $ MACHINE=nrf52840dk-nrf52840 bitbake zephyr-philosophers
 
- You can set up ``MACHINE`` variable can be set up in ``conf/local.conf`` file under the build directory, or via the command line.
+ You can set up ``MACHINE`` variable can be set up in ``conf/local.conf`` file
+ under the build directory, or via the command line.
 
 3. After the build completes, the image file can be found in
    ``build-ohos-zephyr/tmp-newlib/deploy/images/nrf52840dk-nrf52840/``.
@@ -53,12 +55,7 @@ All Scenarios OS Zephyr flavour is based on Zephyr kernel.
 Flashing an application
 =======================
 
-Installing pyOCD
-----------------
-
-pyOCD is an open source Python package for programming and debugging
-Arm Cortex-M microcontrollers using multiple supported types of USB debug probes. 
-It is fully cross-platform, with support for Linux.
+pyOCD is a required host tool used by the flashing mechanism described below:
 
 * To install the latest stable version of pyOCD via `pip <https://pip.pypa.io/en/stable/>`_ as follows:
 
@@ -66,36 +63,14 @@ It is fully cross-platform, with support for Linux.
 
    $ pip install --pre -U pyOCD
 
-* To install the latest pre-release version from the HEAD of the master branch, execute the following command:
-
- .. code-block:: console
-
-   $ pip install --pre -U git+https://github.com/mbedmicro/pyOCD.git
-
-* To install directly from the source by cloning the git repository, do the following:
-
- .. code-block:: console
-
-   $ python setup.py install
-
-* Verify that the board is detected by pyOCD by executing the command:
-
- .. code-block:: console
-
-   $ pyocd-flashtool -l
-
  .. note::
 
    When ``ValueError: The device has no langid`` error is displayed due to lack of 
    permission, perform the `instructions to resolve <https://github.com/pyocd/pyOCD/tree/master/udev>`__.
+   
+* To flash the image, execute the command used to build the image with ``-c flash_usb`` appended.
+  For example, to flash the already built zephyr-philosophers image, execute:
 
-How to flash
-------------
-
-To flash the image, execute the command used to build the image with ``-c flash_usb`` appended.
-For example, to flash the already built zephyr-philosophers image, execute:
-
-.. code-block:: console
+ .. code-block:: console
 
    $ MACHINE=nrf52840dk-nrf52840 bitbake zephyr-philosophers -c flash_usb
-