Docs: Use "site" rather than "blog" in `get_current_blog_id()` docs.

Fixes #35415.


git-svn-id: https://develop.svn.wordpress.org/trunk@36317 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/load.php

@@ -761,13 +761,13 @@ function is_multisite() {
 }
 
 /**
- * Retrieve the current blog ID.
+ * Retrieve the current site ID.
  *
  * @since 3.1.0
  *
  * @global int $blog_id
  *
- * @return int Blog id
+ * @return int Site ID.
  */
 function get_current_blog_id() {
 	global $blog_id;