Move "cursor" position on \r\n sequence after single-dot in a line (#5838)

plugins/managesieve/lib/Roundcube/rcube_sieve_script.php

@@ -1231,9 +1231,12 @@ class rcube_sieve_script
                             $text    .= substr($str, $position, $pos - $position);
                             $position = $pos + 2;
 
-                            if ($str[$position] == "\n"
-                                || ($str[$position] == "\r" && $str[$position + 1] == "\n")
-                            ) {
+                            if ($str[$position] == "\n") {
+                                break;
+                            }
+
+                            if ($str[$position] == "\r" && $str[$position + 1] == "\n") {
+                                $position++;
                                 break;
                             }