Fix typo in method name

program/lib/Roundcube/rcube_html2text.php

@@ -608,7 +608,7 @@ class rcube_html2text
                     $this->width = $p_width;
 
                     // Add citation markers and create <pre> block
-                    $body = preg_replace_callback('/((?:^|\n)>*)([^\n]*)/', array($this, 'blockquote_citation_ballback'), trim($body));
+                    $body = preg_replace_callback('/((?:^|\n)>*)([^\n]*)/', array($this, 'blockquote_citation_callback'), trim($body));
                     $body = '<pre>' . htmlspecialchars($body) . '</pre>';
 
                     $text = substr_replace($text, $body . "\n", $start, $end + 13 - $start);
@@ -624,7 +624,7 @@ class rcube_html2text
     /**
      * Callback function to correctly add citation markers for blockquote contents
      */
-    public function blockquote_citation_ballback($m)
+    public function blockquote_citation_callback($m)
     {
         $line  = ltrim($m[2]);
         $space = $line[0] == '>' ? '' : ' ';