Accessibility: Login and Registration: Improve the invalid username and invalid email messages.

- explicitly informs users they can use their email to log in as an alternative to their username and vice-versa
- shows the `Lost your password?` link only when an wrong password has been entered
- uses a more appropriate copy by changing "invalid" to "unknown"
- removes the all caps `ERROR`

Props subrataemfluence, zalak151291, ryokuhi, SergeyBiryukov, audrasjb, joedolson, marybaum, ramiy, markjaquith, chanthaboune, afercia.
Fixes #43037.

Built from https://develop.svn.wordpress.org/trunk@46417


git-svn-id: http://core.svn.wordpress.org/trunk@46215 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/user.php

@@ -149,10 +149,7 @@ function wp_authenticate_username_password( $user, $username, $password ) {
 	if ( ! $user ) {
 		return new WP_Error(
 			'invalid_username',
-			__( '<strong>ERROR</strong>: Invalid username.' ) .
-			' <a href="' . wp_lostpassword_url() . '">' .
-			__( 'Lost your password?' ) .
-			'</a>'
+			__( 'Unknown username. Check again or try your email address.' )
 		);
 	}
 
@@ -230,10 +227,7 @@ function wp_authenticate_email_password( $user, $email, $password ) {
 	if ( ! $user ) {
 		return new WP_Error(
 			'invalid_email',
-			__( '<strong>ERROR</strong>: Invalid email address.' ) .
-			' <a href="' . wp_lostpassword_url() . '">' .
-			__( 'Lost your password?' ) .
-			'</a>'
+			__( 'Unknown email address. Check again or try your username.' )
 		);
 	}
 

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.3-beta2-46416';
+$wp_version = '5.3-beta2-46417';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.