Hello World: correct typo

exercises/hello-world/GETTING_STARTED.md

 
 ## Iterate through the tests
 
-After your first test passes, remove the `@Ignore` from the next test, and ierate on your solution,
+After your first test passes, remove the `@Ignore` from the next test, and iterate on your solution,
 testing after each change.
 
 ## All the tests pass?  Submit your solution!