Mail: Prevent the last character of names in “From” headers from being trimmed.

When extracting the email and name from a “From” header, the last character of the name is incorrectly trimmed when a space is not included between the name and the opening `<`.

Though the space is required for the header to be compliant with RFC5322 (see https://www.rfc-editor.org/rfc/rfc5322#section-3.4), the absence of a space can be ignored here. PHPMailer accepts the name and email as separate parameters and constructs the header correctly later on.

Props hakanca, mikehansenme, SergeyBiryukov, kovshenin, mattyrob, drewapicture, desrosj.
Fixes #19847.
Built from https://develop.svn.wordpress.org/trunk@53900


git-svn-id: http://core.svn.wordpress.org/trunk@53459 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/pluggable.php

@@ -307,7 +307,7 @@ if ( ! function_exists( 'wp_mail' ) ) :
 							if ( false !== $bracket_pos ) {
 								// Text before the bracketed email is the "From" name.
 								if ( $bracket_pos > 0 ) {
-									$from_name = substr( $content, 0, $bracket_pos - 1 );
+									$from_name = substr( $content, 0, $bracket_pos );
 									$from_name = str_replace( '"', '', $from_name );
 									$from_name = trim( $from_name );
 								}

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.1-alpha-53899';
+$wp_version = '6.1-alpha-53900';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.