Fix bug where wrong words were highlighted on spell-before-send check

CHANGELOG

@@ -1,6 +1,7 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Fix bug where wrong words were highlighted on spell-before-send check
 - Fix handling of URLs with asterisk characters (#1488759)
 - Remove automatic to-lowercase conversion of usernames (#1488715)
 - Fix scrolling quirk in email preview frame using Opera 12 (#1488763)

program/steps/mail/sendmail.inc

@@ -468,6 +468,7 @@ if (!$savedraft) {
   if ($CONFIG['spellcheck_before_send'] && $CONFIG['enable_spellcheck']
     && empty($COMPOSE['spell_checked']) && !empty($message_body)
   ) {
+    $message_body = str_replace("\r\n", "\n", $message_body);
     $spellchecker = new rcube_spellchecker(get_input_value('_lang', RCUBE_INPUT_GPC));
     $spell_result = $spellchecker->check($message_body, $isHtml);