Docs: Document that `get_category_by_slug()` returns `false` if the category doesn't exist.

Props stevenlinx.
Fixes #50277.
Built from https://develop.svn.wordpress.org/trunk@47863


git-svn-id: http://core.svn.wordpress.org/trunk@47639 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/category.php

@@ -175,10 +175,11 @@ function get_category_by_path( $category_path, $full_match = true, $output = OBJ
  * @since 2.3.0
  *
  * @param string $slug The category slug.
- * @return object Category data object
+ * @return object|false Category data object on success, false if not found.
  */
 function get_category_by_slug( $slug ) {
 	$category = get_term_by( 'slug', $slug, 'category' );
+
 	if ( $category ) {
 		_make_cat_compat( $category );
 	}

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.5-alpha-47862';
+$wp_version = '5.5-alpha-47863';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.