Fixing link
```
Please refer to the
- [distributed tracing section of the guide](GUIDE.md#distributed-tracingg)
+ [distributed tracing section of the guide](GUIDE.md#distributed-tracing)
for more detail on how to ensure you get the most out of the Go agent's distributed tracing support.
* Added functions [NewContext](https://godoc.org/github.com/newrelic/go-agent#NewContext)
