Add / correct comments

Marlin/Configuration_adv.h

@@ -2989,7 +2989,7 @@
   #define MAX7219_LOAD_PIN  44
 
   //#define MAX7219_GCODE          // Add the M7219 G-code to control the LED matrix
-  #define MAX7219_INIT_TEST    2   // Do a test pattern at initialization (Set to 2 for spiral)
+  #define MAX7219_INIT_TEST    2   // Test pattern at startup: 0=none, 1=sweep, 2=spiral
   #define MAX7219_NUMBER_UNITS 1   // Number of Max7219 units in chain.
   #define MAX7219_ROTATE       0   // Rotate the display clockwise (in multiples of +/- 90°)
                                    // connector at:  right=0   bottom=-90  top=90  left=180

Marlin/src/gcode/queue.cpp

@@ -361,6 +361,10 @@ inline void process_stream_char(const char c, uint8_t &sis, char (&buff)[MAX_CMD
     sis = PS_EOL;               // Skip the rest on overflow
 }
 
+/**
+ * Handle a line being completed. For an empty line
+ * keep sensor readings going and watchdog alive.
+ */
 inline bool process_line_done(uint8_t &sis, char (&buff)[MAX_CMD_SIZE], int &ind) {
   sis = PS_NORMAL;
   buff[ind] = 0;

Marlin/src/pins/mega/pins_GT2560_V3.h

@@ -22,7 +22,7 @@
 #pragma once
 
 /**
- * GT3560 RevB + GT2560 V3.0 + GT2560 V3.1 + GT2560 V4.0 pin assignment
+ * GT2560 RevB + GT2560 V3.0 + GT2560 V3.1 + GT2560 V4.0 pin assignment
  */
 
 #if !defined(__AVR_ATmega1280__) && !defined(__AVR_ATmega2560__)