document always hook with fail fast flag (#858)

Author: cgcgbcbc

readme.md

@@ -436,6 +436,8 @@ AVA lets you register hooks that are run before and after your tests. This allow
 
 `test.beforeEach()` registers a hook to be run before each test in your test file. Similarly `test.afterEach()` a hook to be run after each test. Use `test.afterEach.always()` to register an after hook that is called even if other test hooks, or the test itself, fail. `.always()` hooks are ideal for cleanup tasks.
 
+**Note**: If the `--fail-fast` flag is specified, AVA will stop after the first test failure and the `.always` hook will **not** run.
+
 Like `test()` these methods take an optional title and a callback function. The title is shown if your hook fails to execute. The callback is called with an [execution object](#t).
 
 `before` hooks execute before `beforeEach` hooks. `afterEach` hooks execute before `after` hooks. Within their category the hooks execute in the order they were defined.