doc: correct parameters in fs and stream documentation

PR-URL: #39984
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

doc/api/fs.md

@@ -2632,7 +2632,7 @@ changes:
 Asynchronously creates a directory.
 
 The callback is given a possible exception and, if `recursive` is `true`, the
-first directory path created, `(err, [path])`.
+first directory path created, `(err[, path])`.
 `path` can still be `undefined` when `recursive` is `true`, if no directory was
 created.
 
@@ -4854,7 +4854,7 @@ Returns the number of `bytesRead`.
 For detailed information, see the documentation of the asynchronous version of
 this API: [`fs.read()`][].
 
-### `fs.readSync(fd, buffer, [options])`
+### `fs.readSync(fd, buffer[, options])`
 <!-- YAML
 added:
  - v13.13.0

doc/api/stream.md

@@ -2042,7 +2042,7 @@ await finished(compose(s1, s2, s3));
 console.log(res); // prints 'HELLOWORLD'
 ```
 
-### `stream.Readable.from(iterable, [options])`
+### `stream.Readable.from(iterable[, options])`
 <!-- YAML
 added:
   - v12.3.0