Docs: Add @param and @return description for sanitize_hex_color_no_hash().

Follow-up to [20936], [21354], [37283], [60709].

Props rollybueno, SergeyBiryukov.
See #63166.

git-svn-id: https://develop.svn.wordpress.org/trunk@60714 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-includes/formatting.php

@@ -6411,8 +6411,9 @@ function sanitize_hex_color( $color ) {
  *
  * @since 3.4.0
  *
- * @param string $color
- * @return string|null
+ * @param string $color The color value to sanitize. Can be with or without a #.
+ * @return string|null The sanitized hex color without the hash prefix,
+ *                     empty string if input is empty, or null if invalid.
  */
 function sanitize_hex_color_no_hash( $color ) {
 	$color = ltrim( $color, '#' );