Login and Registration: Introduce classes wp-login.php footer links.

This introduces classes for the "Log in", "Register" and "Lost your password?" links in the footer of `wp-login.php` forms so that they may be easily targeted for individual styling.

The new classes are:
- `.wp-login-log-in`
- `.wp-login-register`
- `.wp-login-lost-password`

Props wparslan, thomasplevy, rajinsharwar, audrasjb, joedolson, costdev.
Fixes #57590.

git-svn-id: https://develop.svn.wordpress.org/trunk@56628 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-login.php

@@ -861,11 +861,11 @@ function wp_login_viewport_meta() {
 		</form>
 
 		<p id="nav">
-			<a href="<?php echo esc_url( wp_login_url() ); ?>"><?php _e( 'Log in' ); ?></a>
+			<a class="wp-login-log-in" href="<?php echo esc_url( wp_login_url() ); ?>"><?php _e( 'Log in' ); ?></a>
 			<?php
 
 			if ( get_option( 'users_can_register' ) ) {
-				$registration_url = sprintf( '<a href="%s">%s</a>', esc_url( wp_registration_url() ), __( 'Register' ) );
+				$registration_url = sprintf( '<a class="wp-login-register" href="%s">%s</a>', esc_url( wp_registration_url() ), __( 'Register' ) );
 
 				echo esc_html( $login_link_separator );
 
@@ -1007,11 +1007,11 @@ function wp_login_viewport_meta() {
 		</form>
 
 		<p id="nav">
-			<a href="<?php echo esc_url( wp_login_url() ); ?>"><?php _e( 'Log in' ); ?></a>
+			<a class="wp-login-log-in" href="<?php echo esc_url( wp_login_url() ); ?>"><?php _e( 'Log in' ); ?></a>
 			<?php
 
 			if ( get_option( 'users_can_register' ) ) {
-				$registration_url = sprintf( '<a href="%s">%s</a>', esc_url( wp_registration_url() ), __( 'Register' ) );
+				$registration_url = sprintf( '<a class="wp-login-register" href="%s">%s</a>', esc_url( wp_registration_url() ), __( 'Register' ) );
 
 				echo esc_html( $login_link_separator );
 
@@ -1112,12 +1112,12 @@ function wp_login_viewport_meta() {
 		</form>
 
 		<p id="nav">
-			<a href="<?php echo esc_url( wp_login_url() ); ?>"><?php _e( 'Log in' ); ?></a>
+			<a class="wp-login-log-in" href="<?php echo esc_url( wp_login_url() ); ?>"><?php _e( 'Log in' ); ?></a>
 			<?php
 
 			echo esc_html( $login_link_separator );
 
-			$html_link = sprintf( '<a href="%s">%s</a>', esc_url( wp_lostpassword_url() ), __( 'Lost your password?' ) );
+			$html_link = sprintf( '<a class="wp-login-lost-password" href="%s">%s</a>', esc_url( wp_lostpassword_url() ), __( 'Lost your password?' ) );
 
 			/** This filter is documented in wp-login.php */
 			echo apply_filters( 'lost_password_html_link', $html_link );
@@ -1481,15 +1481,15 @@ function wp_login_viewport_meta() {
 				<?php
 
 				if ( get_option( 'users_can_register' ) ) {
-					$registration_url = sprintf( '<a href="%s">%s</a>', esc_url( wp_registration_url() ), __( 'Register' ) );
+					$registration_url = sprintf( '<a class="wp-login-register" href="%s">%s</a>', esc_url( wp_registration_url() ), __( 'Register' ) );
 
 					/** This filter is documented in wp-includes/general-template.php */
 					echo apply_filters( 'register', $registration_url );
 
 					echo esc_html( $login_link_separator );
 				}
 
-				$html_link = sprintf( '<a href="%s">%s</a>', esc_url( wp_lostpassword_url() ), __( 'Lost your password?' ) );
+				$html_link = sprintf( '<a class="wp-login-lost-password" href="%s">%s</a>', esc_url( wp_lostpassword_url() ), __( 'Lost your password?' ) );
 
 				/**
 				 * Filters the link that allows the user to reset the lost password.