Update testdriver.md (#11261)

Fix link to list of special keys.

docs/_writing-tests/testdriver.md

@@ -45,7 +45,7 @@ Note that if the element that's keys need to be send to does not have
 a unique ID, the document must not have any DOM mutations made
 between the function being called and the promise settling.
 
-To send special keys, one must send the respective key's codepoint. Since this uses the WebDriver protocol, you can find a list for code points to special keys in the spec (here)[https://w3c.github.io/webdriver/webdriver-spec.html#keyboard-actions].
+To send special keys, one must send the respective key's codepoint. Since this uses the WebDriver protocol, you can find a [list for code points to special keys in the spec](https://w3c.github.io/webdriver/webdriver-spec.html#keyboard-actions).
 For example, to send the tab key you would send "\uE004".
 
 [testharness]: {{ site.baseurl }}{% link _writing-tests/testharness.md %}