Add LCD_STR_SOLID_BLOCK to represent \xFF

Firmware/lcd.h

@@ -200,6 +200,7 @@ private:
 #define LCD_STR_FEEDRATE     "\x06"
 #define LCD_STR_CLOCK        "\x07"
 #define LCD_STR_ARROW_RIGHT  "\x7E" //from the default character set
+#define LCD_STR_SOLID_BLOCK "\xFF"  //from the default character set
 
 extern void lcd_set_custom_characters(void);
 extern void lcd_set_custom_characters_nextpage(void);

Firmware/menu.cpp

@@ -570,7 +570,7 @@ void menu_progressbar_update(uint16_t newVal)
 		newCnt = LCD_WIDTH;
 	while (newCnt > progressbar_block_count)
 	{
-		lcd_print('\xFF');
+		lcd_print(LCD_STR_SOLID_BLOCK[0]);
 		progressbar_block_count++;
 	}
 }

Firmware/ultralcd.cpp

@@ -8646,7 +8646,7 @@ static void lcd_connect_printer() {
 			i = 0; 
 			lcd_puts_at_P(0, 3, PSTR("                    "));
 		}
-		if (i!=0) lcd_puts_at_P((i * 20) / (NC_BUTTON_LONG_PRESS * 10), 3, "\xFF");
+		if (i!=0) lcd_puts_at_P((i * 20) / (NC_BUTTON_LONG_PRESS * 10), 3, LCD_STR_SOLID_BLOCK[0]);
 		if (i == NC_BUTTON_LONG_PRESS * 10) {
 			no_response = false;
 		}