doc: add missing parameter types

Both of the `clearTimeout()` and `clearInterval()` functions in the
`timers` lib accepts the ID of the `Timeout` object returned by the
functions in a number or string type, e.g.

```js
const t = setTimeout(console.log, 5000, 'test');

clearTimeout(t[Symbol.toPrimitive]());
```

PR-URL: nodejs#39013
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/timers.md

@@ -305,7 +305,8 @@ Cancels an `Immediate` object created by [`setImmediate()`][].
 added: v0.0.1
 -->
 
-* `timeout` {Timeout} A `Timeout` object as returned by [`setInterval()`][].
+* `timeout` {Timeout|string|number} A `Timeout` object as returned by [`setInterval()`][]
+  or the [primitive][] of the `Timeout` object as a string or a number.
 
 Cancels a `Timeout` object created by [`setInterval()`][].
 
@@ -314,7 +315,8 @@ Cancels a `Timeout` object created by [`setInterval()`][].
 added: v0.0.1
 -->
 
-* `timeout` {Timeout} A `Timeout` object as returned by [`setTimeout()`][].
+* `timeout` {Timeout|string|number} A `Timeout` object as returned by [`setTimeout()`][]
+  or the [primitive][] of the `Timeout` object as a string or a number.
 
 Cancels a `Timeout` object created by [`setTimeout()`][].
 
@@ -329,3 +331,4 @@ Cancels a `Timeout` object created by [`setTimeout()`][].
 [`setTimeout()`]: timers.md#timers_settimeout_callback_delay_args
 [`util.promisify()`]: util.md#util_util_promisify_original
 [`worker_threads`]: worker_threads.md
+[primitive]: timers.md#timers_timeout_symbol_toprimitive