Terminal: Ensure a \t always advances by at least one column

Author: https://github.com/bugaevc
Commit: 053419dc3c
Pull-request: https://github.com/SerenityOS/serenity/pull/580

Libraries/LibVT/Terminal.cpp

@@ -799,7 +799,7 @@ void Terminal::on_char(u8 ch)
         m_client.beep();
         return;
     case '\t': {
-        for (unsigned i = m_cursor_column; i < columns(); ++i) {
+        for (unsigned i = m_cursor_column + 1; i < columns(); ++i) {
             if (m_horizontal_tabs[i]) {
                 set_cursor(m_cursor_row, i);
                 return;