fixup! test: clean tmpdir on process exit

Suggestions by Rich Trott

test/common/README.md

@@ -906,11 +906,12 @@ The realpath of the testing temporary directory.
 
 Deletes and recreates the testing temporary directory.
 
-The first time refresh is run it adds a listener to process `'exit'` that
+The first time `refresh()` runs,  it adds a listener to process `'exit'` that
 cleans the temporary directory. Thus, every file under `tmpdir.path` needs to
 be closed before the test completes. A good way to do this is to add a
-listener to process `'beforeExit'`. If a file needs to be left open until Node
-completes, use a child process and call `refresh` only in the parent.
+listener to process `'beforeExit'`. If a file needs to be left open until
+Node.js completes, use a child process and call `refresh()` only in the
+parent.
 
 ## WPT Module