[DOC] - Making/Receiving phone calls guide requires SWML example

[Manny-r31]

Describe the requested update

https://developer.signalwire.com/voice/getting-started/making-and-receiving-phone-calls requires an example for creating a call via SW create a call API

Reason for the request

To allow for SWML to be easy to start with across the board.

Sections to be updated

https://developer.signalwire.com/voice/getting-started/making-and-receiving-phone-calls

Related Issues or PRs

This is a sub-issue of #208