Fix whitespace errors (no code changes)

(1) convert tabs to spaces
(2) remove trailing whitespace

src/Fl_Message.cxx

@@ -503,7 +503,7 @@ const char *Fl_Message::input_innards(const char *fmt, va_list ap, const char *d
   will be reset to an empty title (the default for all dialogs) after
   that call.
 
-  \param[in] title	window label, string copied internally
+  \param[in] title      window label, string copied internally
 */
 void Fl_Message::message_title(const char *title) {
   if (message_title_) {
@@ -527,7 +527,7 @@ void Fl_Message::message_title(const char *title) {
   The \p title string is copied internally, so that you can use a
   local variable or free the string immediately after this call.
 
-  \param[in] title	default window label, string copied internally
+  \param[in] title      default window label, string copied internally
 */
 void Fl_Message::message_title_default(const char *title) {
   if (message_title_default_) {

src/drivers/X11/Fl_X11_Window_Driver.cxx

@@ -95,7 +95,7 @@ void Fl_X11_Window_Driver::decorated_win_size(int &w, int &h)
     attributes.height -= (attributes.width - w_attributes.width);
     attributes.width = w_attributes.width;
   }
-  
+
   int nscreen = screen_num();
   float s = Fl::screen_driver()->scale(nscreen);
   w = attributes.width / s;

test/device.cxx

@@ -602,7 +602,7 @@ void copy(Fl_Widget *, void *data) {
       }
     }
   }
-  
+
   if (strcmp(operation, "fl_capture_window()") == 0) {
     Fl_Window *win = target->as_window() ? target->as_window() : target->window();
     int X = target->as_window() ? 0 : target->x();