Typos (#814)

* Typos

* Fix function names

Co-authored-by: Marcin Romaszewicz <47459980+deepmap-marcinr@users.noreply.github.com>

Author: Jleagle

request_helpers.go

@@ -14,7 +14,7 @@
 package testutil
 
 // This is a set of fluent request builders for tests, which help us to
-// simplify constructing and unmarshaling test objects. For example, to post
+// simplify constructing and unmarshalling test objects. For example, to post
 // a body and return a response, you would do something like:
 //
 //   var body RequestBody