Edit wisun_intro.md

Edit file, mostly for formatting and minor rearranging of some content.

Author: Amanda Butler

docs/reference/technology/mesh/wisun_intro.md

@@ -1,14 +1,12 @@
-### Introduction to Wi-SUN networking stack
-Initial version of Mbed Wi-SUN networking stack was introduced in Mbed OS release 5.12.
+#### Wi-SUN
 
-More details about Wi-SUN can be found from [Wi-SUN Alliance site](https://www.wi-sun.org).
+The Wi-SUN Field Area Network (FAN) is based on open standards from IEEE802, IETF, ANSI/TIA and ETSI.
 
-#### Why to use Wi-SUN Alliance FAN (Field Area Network) profile
-Wi-SUN FAN is based on open standards from IEEE802, IETF, ANSI/TIA and ETSI.
+Wi-SUN FAN operates on license-exempt sub-GHz RF band and uses frequency hopping to lower interference. Therefore, Wi-SUN is well suited for outdoor installations and dense urban neighborhoods.
 
-Wi-SUN FAN operates on license-exempt sub-GHz RF band and is using frequency hopping to lower interference. Therefore Wi-SUN is well suited for outdoor installations and dense urban neighborhoods.
+The Mbed OS Wi-SUN stack is built on IPv6 over Low power Wireless Personal Area Networks (6LoWPAN), which itself builds on IEEE 802.15.4 to offer IP-based networking. Internet Protocol (IP) provides the core mechanism for relaying datagrams across IP networks, and its routing capabilities enable internetworking.
 
-The Mbed Wi-SUN stack is built on IPv6 over Low power Wireless Personal Area Networks (6LoWPAN), which itself builds on IEEE 802.15.4 to offer IP-based networking. Internet Protocol (IP) provides the core mechanism for relaying datagrams across IP networks, and its routing capabilities enable internetworking.
+You can find more details about Wi-SUN at the [Wi-SUN Alliance site](https://www.wi-sun.org).
 
 #### Mbed Wi-SUN API
 
@@ -18,18 +16,21 @@ Mbed OS provides the [Mesh C++ API](../apis/mesh-api.html) for building Wi-SUN a
 - For the socket communication over the Wi-SUN network, use the [Mbed sockets API](../apis/network-socket.html).
 
 ##### Nanostack Wi-SUN API
+
 Mbed Wi-SUN is implemented in the Nanostack library that provides a set of C API headers with more functionalities. The [nanostack folder](https://github.com/ARMmbed/mbed-os/tree/master/features/nanostack/sal-stack-nanostack/nanostack) has the following header files that can be used with Wi-SUN:
+
 - `net_interface.h` for initializing, starting and stopping a Wi-SUN interface.
-- `ws_management_api.h` for configuring device behaviour.
+- `ws_management_api.h` for configuring device behavior.
 - `ws_bbr_api.h` for Wi-SUN backbone border router application interface.
 
 #### Mbed Wi-SUN examples
+
 Mbed Wi-SUN network consists of routers and border router(s). Mbed OS provides example applications to build Wi-SUN application.
 
 ##### Router
 
-- An example using the [Mesh C++ API](../apis/mesh-api.html) for building a Wi-SUN router device can be found from [mesh minimal example](https://github.com/ARMmbed/mbed-os-example-mesh-minimal).
+You can find an example using the [Mesh C++ API](../apis/mesh-api.html) for building a Wi-SUN router device in the [mesh minimal example](https://github.com/ARMmbed/mbed-os-example-mesh-minimal).
 
-#####Border router
+##### Border router
 
-- An example using the [Nanostack API](https://github.com/ARMmbed/mbed-os/tree/master/features/nanostack/sal-stack-nanostack/nanostack) for building a Wi-SUN border router can be found from [nanostack border router](https://github.com/ARMmbed/nanostack-border-router).
+You can find an example using the [Nanostack API](https://github.com/ARMmbed/mbed-os/tree/master/features/nanostack/sal-stack-nanostack/nanostack) to biuld a Wi-SUN border router at [nanostack border router](https://github.com/ARMmbed/nanostack-border-router).