diff --git a/core/includes/form.inc b/core/includes/form.inc
index 84f4b14..754132a 100644
--- a/core/includes/form.inc
+++ b/core/includes/form.inc
@@ -859,20 +859,22 @@ function template_preprocess_select(&$variables) {
  *   An associative array containing the following key-value pairs:
  *   - #multiple: Optional Boolean indicating if the user may select more than
  *     one item.
- *   - #options: A associative array of options to render as HTML. Each array
- *     value can be a string, array, or an object with an 'option' property:
- *     - A string or integer key mapped to a translated string is interpreted as
- *     a single HTML option element. Do not use placeholders to sanitize data:
- *     doing so will lead to double-escaping. Note that the key will be visible
- *     in the HTML and could be modified by malicious users, so don't put
- *     sensitive information in it and sanitize it before use.
- *     - A translated string key mapped to an array indicates a group of
+ *   - #options: An associative array of options to render as HTML. Each array
+ *     value can be a string, an array, or an object with an 'option' property:
+ *     - A string or integer key whose value is a translated string is
+ *     interpreted as a single HTML option element. Do not use placeholders
+ *     which sanitize data: doing so will lead to double-escaping. Note that the
+ *     key will be visible in the HTML and could be modified by malicious users,
+ *     so don't put sensitive information in it and sanitize it before use if
+ *     based on user input.
+ *     - A translated string key whose value is an array indicates a group of
  *     options. The translated string is used as the label attribute for the
  *     optgroup. Do not use placeholders to sanitize data: doing so will lead to
- *     double-escaping. The array should contain the options you wish to group.
+ *     double-escaping. The array should contain the options you wish to group
+ *     and should follow the syntax of $element['#options'].
  *     Groups are output as HTML optgroup elements.
- *     - If the function encounters a string or integer key mapped to an object
- *     with an 'option' property, the key is ignored, the contents of the
+ *     - If the function encounters a string or integer key whose value is an
+ *     object with an 'option' property, the key is ignored, the contents of the
  *     option property are interpreted as $element['#options'], and the
  *     resulting HTML is added to the output.
  *   - #value: Optional integer, string, or array representing which option(s)