doc: clarify QUIC stream state wording

When the body option is omitted, no FIN is sent immediately and the
stream's outgoing side remains writable. The stream can still be
written later via stream.setBody() or the writer.

Avoid describing the outgoing stream itself as half-closed, since the
outgoing side is one half of the stream state.

Fixes: #63655
Signed-off-by: EduardF1 <50618110+EduardF1@users.noreply.github.com>
PR-URL: #63660
Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: EduardF1

doc/api/quic.md

@@ -1280,8 +1280,8 @@ added: v23.8.0
   * `body` {string | ArrayBuffer | SharedArrayBuffer | ArrayBufferView |
     Blob | FileHandle | AsyncIterable | Iterable | Promise | null}
     The outbound body source. See [`stream.setBody()`][] for details on
-    supported types. When omitted, the stream starts half-closed (writable
-    side open, no body queued).
+    supported types. When omitted, the stream's outgoing side remains
+    writable with no body queued; no FIN is sent immediately.
   * `headers` {Object} Initial request or response headers to send. Only
     used when the session supports headers (e.g. HTTP/3). If `body` is not
     specified and `headers` is provided, the stream is treated as
@@ -1308,7 +1308,8 @@ added: v23.8.0
 * Returns: {Promise} for a {quic.QuicStream}
 
 Open a new bidirectional stream. If the `body` option is not specified,
-the outgoing stream will be half-closed. The `priority` and `incremental`
+the stream's outgoing side remains writable and no FIN is sent
+immediately. The `priority` and `incremental`
 options are only used when the session supports priority (e.g. HTTP/3).
 The `headers`, `onheaders`, `ontrailers`, `oninfo`, and `onwanttrailers`
 options are only used when the session supports headers (e.g. HTTP/3).
@@ -1323,7 +1324,8 @@ added: v23.8.0
   * `body` {string | ArrayBuffer | SharedArrayBuffer | ArrayBufferView |
     Blob | FileHandle | AsyncIterable | Iterable | Promise | null}
     The outbound body source. See [`stream.setBody()`][] for details on
-    supported types. When omitted, the stream is closed immediately.
+    supported types. When omitted, the stream's outgoing side remains
+    writable with no body queued; no FIN is sent immediately.
   * `headers` {Object} Initial request headers to send.
   * `priority` {string} The priority level of the stream. One of `'high'`,
     `'default'`, or `'low'`. **Default:** `'default'`.
@@ -1345,7 +1347,8 @@ added: v23.8.0
 * Returns: {Promise} for a {quic.QuicStream}
 
 Open a new unidirectional stream. If the `body` option is not specified,
-the outgoing stream will be closed. The `priority` and `incremental`
+the stream's outgoing side remains writable and no FIN is sent
+immediately. The `priority` and `incremental`
 options are only used when the session supports priority (e.g. HTTP/3).
 
 ### `session.path`