fs: expose copy-on-write flags for fs.copyFile()

This commit exposes the UV_FS_COPYFILE_FICLONE and
UV_FS_COPYFILE_FICLONE_FORCE flags added in libuv 1.20.0.

Fixes: nodejs#19152
PR-URL: nodejs#19759
Fixes: nodejs#19152
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/fs.md

@@ -3384,6 +3384,34 @@ The following constants are meant for use with [`fs.copyFile()`][].
   </tr>
 </table>
 
+### File Copy Constants
+
+The following constants are meant for use with [`fs.copyFile()`][].
+
+<table>
+  <tr>
+    <th>Constant</th>
+    <th>Description</th>
+  </tr>
+  <tr>
+    <td><code>COPYFILE_EXCL</code></td>
+    <td>If present, the copy operation will fail with an error if the
+    destination path already exists.</td>
+  </tr>
+  <tr>
+    <td><code>COPYFILE_FICLONE</code></td>
+    <td>If present, the copy operation will attempt to create a
+    copy-on-write reflink. If the underlying platform does not support
+    copy-on-write, then a fallback copy mechanism is used.</td>
+  </tr>
+  <tr>
+    <td><code>COPYFILE_FICLONE_FORCE</code></td>
+    <td>If present, the copy operation will attempt to create a
+    copy-on-write reflink. If the underlying platform does not support
+    copy-on-write, then the operation will fail with an error.</td>
+  </tr>
+</table>
+
 ### File Open Constants
 
 The following constants are meant for use with `fs.open()`.