docs: correct allowedMetaFields (#5227)

docs/uploader/aws-s3-multipart.mdx

@@ -386,9 +386,9 @@ The default implementation calls out to Companion’s S3 signing endpoints.
 Pass an array of field names to limit the metadata fields that will be added to
 upload as query parameters.
 
-- Set this to `['name']` to only send the `name` field.
-- Set this to `null` (the default) to send _all_ metadata fields.
-- Set this to an empty array `[]` to not send any fields.
+- Set it to `false` to not send any fields (or an empty array).
+- Set it to `['name']` to only send the `name` field.
+- Set it to `true` (the default) to send _all_ metadata fields.
 
 <details>
 <summary>Deprecated options</summary>

docs/uploader/tus.mdx

@@ -215,9 +215,9 @@ uploads as
 [Tus Metadata](https://tus.io/protocols/resumable-upload.html#upload-metadata)
 (`Array`, default: `null`).
 
-- Set this to `['name']` to only send the `name` field.
-- Set this to `null` (the default) to send _all_ metadata fields.
-- Set this to an empty array `[]` to not send any fields.
+- Set it to `false` to not send any fields (or an empty array).
+- Set it to `['name']` to only send the `name` field.
+- Set it to `true` (the default) to send _all_ metadata fields.
 
 #### `limit`
 

docs/uploader/xhr.mdx

@@ -111,9 +111,9 @@ defaults to `'file'`.
 Pass an array of field names to limit the metadata fields that will be added to
 upload.
 
-- Set this to an empty array `[]` to not send any fields.
-- Set this to `['name']` to only send the `name` field.
-- Set this to `null` (the default) to send _all_ metadata fields.
+- Set it to `false` to not send any fields (or an empty array).
+- Set it to `['name']` to only send the `name` field.
+- Set it to `true` (the default) to send _all_ metadata fields.
 
 If the [`formData`](#formData-true) option is set to false, `metaFields` is
 ignored.