Docs: Link to the "Conditional Tags" article in the Theme Developer Handbook from the descriptions for a variety of core conditional tag functions.

These notations largely serve to direct consumers (of both the source and the parsed code reference) to extended information on individual and related conditional tags throughout WordPress. The changeset also standardizes corresponding DocBlock summaries to use third-person singular verbs.

Notations been added for the following functions:

* comments_open()
* email exists()
* has_excerpt()
* has_post_thumbnail()
* has_tag()
* in_category()
* in_the_loop()
* is_404()
* is_active_sidebar()
* is_active_widget()
* is_admin()
* is_admin_bar_showing()
* is_archive()
* is_attachment()
* is_author()
* is_blog_installed()
* is_category()
* is_comments_popup()
* is_date()
* is_day()
* is_dynamic_sidebar()
* is_feed()
* is_front_page()
* is_home()
* is_local_attachment()
* is_main_query
* is_month()
* is_multi_author
* is_new_day()
* is_page()
* is_page_template()
* is_paged()
* is_plugin_active()
* is_plugin_active_for_network()
* is_plugin_inactive()
* is_plugin_page()
* is_post_type_archive()
* is_preview()
* is_rtl()
* is_search()
* is_single()
* is_singular()
* is_sticky()
* is_tag()
* is_tax()
* is_taxonomy_hierarchical()
* is_time()
* is_trackback()
* is_user_logged_in()
* is_year()
* pings_open()
* post_type_exists()
* taxonomy_exists()
* term_exists()
* username exists()
* wp_attachment_is_image()
* wp_script_is()

Props janalwin.
Fixes #43254.

Built from https://develop.svn.wordpress.org/trunk@42710


git-svn-id: http://core.svn.wordpress.org/trunk@42538 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/category-template.php

@@ -221,7 +221,7 @@ function get_the_category_list( $separator = '', $parents = '', $post_id = false
 }
 
 /**
- * Check if the current post is within any of the given categories.
+ * Checks if the current post is within any of the given categories.
  *
  * The given categories are checked against the post's categories' term_ids, names and slugs.
  * Categories given as integers will only be checked against the post's categories' term_ids.
@@ -231,6 +231,10 @@ function get_the_category_list( $separator = '', $parents = '', $post_id = false
  * Prior to v2.7, only one category could be compared: in_category( $single_category ).
  * Prior to v2.7, this function could only be used in the WordPress Loop.
  * As of 2.7, the function can be used anywhere if it is provided a post ID or post object.
+ * 
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/ 
+ * Conditional Tags} article in the Theme Developer Handbook.
  *
  * @since 1.2.0
  *
@@ -1406,7 +1410,7 @@ function has_category( $category = '', $post = null ) {
 }
 
 /**
- * Check if the current post has any of given tags.
+ * Checks if the current post has any of given tags.
  *
  * The given tags are checked against the post's tags' term_ids, names and slugs.
  * Tags given as integers will only be checked against the post's tags' term_ids.
@@ -1415,6 +1419,10 @@ function has_category( $category = '', $post = null ) {
  * Prior to v2.7 of WordPress, tags given as integers would also be checked against the post's tags' names and slugs (in addition to term_ids)
  * Prior to v2.7, this function could only be used in the WordPress Loop.
  * As of 2.7, the function can be used anywhere if it is provided a post ID or post object.
+ * 
+ * For more information on this and similar theme functions, check out
+ * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/ 
+ * Conditional Tags} article in the Theme Developer Handbook.
  *
  * @since 2.6.0
  *