Add more info to goroutine sample README (#407)

Author: yuandrew

branch/README.md

@@ -1,4 +1,8 @@
 ## Parallel Activities
+
+This sample demonstrates how to kick off multiple activities in parallel and
+then synchronously await their results once all have completed.
+
 <!-- @@@SNIPSTART samples-go-branch-readme -->
 Make sure the [Temporal Server is running locally](https://learn.temporal.io/getting_started/go/dev_environment/#set-up-a-local-temporal-service-for-development-with-temporal-cli).
 

goroutine/README.md

@@ -1,7 +1,10 @@
 This sample Workflow Definition demonstrates how to use multiple workflow safe goroutines (instead of native ones) to
 process multiple sequences of activities in parallel.
 In Temporal Workflow Definition, you should not use `go` keyword to start goroutines. Instead, you use the `workflow.Go`
-function.
+function, which spawns a coroutine that is never run in parallel, but instead deterministically. 
+
+To see more information on goroutines and multithreading, see our
+[docs on Go SDK multithreading](https://docs.temporal.io/develop/go/go-sdk-multithreading).
 
 ### Steps to run this sample:
 

goroutine/goroutine_workflow.go

@@ -9,7 +9,7 @@ import (
 )
 
 /**
-* This sample workflow demonstrates how to use multiple Temporal gorotinues (instead of native goroutine) to process a
+* This sample workflow demonstrates how to use multiple Temporal goroutines (instead of native goroutine) to process a
 * a sequence of activities in parallel.
 * In Temporal workflow, you should create goroutines using workflow.Go method.
  */