Login and Registration: Improve "email already exists" registration e…

…rror message.

Adds the `wp_login_url()` login link to the Error message to be more helpful to users when their user email already is registered.

Improves the error message to more clearly communicate next step.

Follow-up to [16009], [22124], [31963].

Props andynick, costdev, dansoschin, sabernhardt, webcommsat.
Fixes #53631.

git-svn-id: https://develop.svn.wordpress.org/trunk@52074 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/ms-functions.php

@@ -538,7 +538,14 @@ function wpmu_validate_user_signup( $user_name, $user_email ) {
 
 	// Check if the email address has been used already.
 	if ( email_exists( $user_email ) ) {
-		$errors->add( 'user_email', __( 'Sorry, that email address is already used!' ) );
+		$errors->add(
+			'user_email',
+			sprintf(
+				/* translators: %s: Link to the login page. */
+				__( '<strong>Error:</strong> This email address is already registered. <a href="%s">Log in</a> with this address or choose another one.' ),
+				wp_login_url()
+			)
+		);
 	}
 
 	// Has someone already signed up for this username?

src/wp-includes/user.php

@@ -3110,7 +3110,14 @@ function register_new_user( $user_login, $user_email ) {
 		$errors->add( 'invalid_email', __( '<strong>Error</strong>: The email address isn&#8217;t correct.' ) );
 		$user_email = '';
 	} elseif ( email_exists( $user_email ) ) {
-		$errors->add( 'email_exists', __( '<strong>Error</strong>: This email is already registered. Please choose another one.' ) );
+		$errors->add(
+			'email_exists',
+			sprintf(
+				/* translators: %s: Link to the login page. */
+				__( '<strong>Error:</strong> This email address is already registered. <a href="%s">Log in</a> with this address or choose another one.' ),
+				wp_login_url()
+			)
+		);
 	}
 
 	/**