WindowServer+LibVT: Convert some dbgprintf() to dbg()

These kept annoying me, because these were the only two lines in the default
boot log that went unattributed.

Libraries/LibVT/TerminalWidget.cpp

@@ -106,7 +106,7 @@ TerminalWidget::TerminalWidget(int ptm_fd, bool automatic_size_policy, RefPtr<Co
     };
     set_scroll_length(m_config->read_num_entry("Window", "ScrollLength", 4));
 
-    dbgprintf("Terminal: Load config file from %s\n", m_config->file_name().characters());
+    dbg() << "Load config file from " << m_config->file_name();
     m_cursor_blink_timer->set_interval(m_config->read_num_entry("Text",
         "CursorBlinkInterval",
         500));

Services/WindowServer/main.cpp

@@ -111,7 +111,7 @@ int main(int, char**)
         return 1;
     }
 
-    dbgprintf("Entering WindowServer main loop.\n");
+    dbg() << "Entering WindowServer main loop";
     loop.exec();
     ASSERT_NOT_REACHED();
 }