docs: fix unstable

Author: Jiralite

README.md

@@ -213,10 +213,8 @@ extension has the following configuration options:
   [ImportCompletions](./docs/ImportCompletions.md) for more information.)
 - `deno.testing.args`: Arguments to use when running tests via the Test
   Explorer. Defaults to `[ \"--allow-all\" ]`.
-- `deno.unstable`: Controls if code will be executed with Deno's unstable APIs.
-  Affects execution which is triggered through the extension, such as test code
-  lenses. This is the equivalent to using `--unstable` on the command line.
-  _boolean, default `false`_
+- `deno.unstable`: Controls which `--unstable-*` features tests will be run.
+  _array of strings, default `[]`_.
 
 ## Compatibility