🎨 Fix spelling, whitespace

Marlin/src/feature/meatpack.cpp

@@ -26,7 +26,7 @@
  * Algorithm & Implementation: Scott Mudge - mail@scottmudge.com
  * Date: Dec. 2020
  *
- * Character Frequencies from ~30 MB of comment-stripped gcode:
+ * Character Frequencies from ~30 MB of comment-stripped G-code:
  *  '1' -> 4451136    '4' -> 1353273   '\n' -> 1087683    '-' ->   90242
  *  '0' -> 4253577    '9' -> 1352147    'G' -> 1075806    'Z' ->   34109
  *  ' ' -> 3053297    '3' -> 1262929    'X' ->  975742    'M' ->   11879

Marlin/src/feature/meatpack.h

@@ -29,7 +29,7 @@
  * Specifically optimized for 3D printing G-Code, this is a zero-cost data compression method
  * which packs ~180-190% more data into the same amount of bytes going to the CNC controller.
  * As a majority of G-Code can be represented by a restricted alphabet, I performed histogram
- * analysis on a wide variety of 3D printing gcode samples, and found ~93% of all gcode could
+ * analysis on a wide variety of 3D printing G-code samples, and found ~93% of all G-code could
  * be represented by the same 15-character alphabet.
  *
  * This allowed me to design a system of packing 2 8-bit characters into a single byte, assuming
@@ -38,7 +38,7 @@
  *
  * Combined with some logic to allow commingling of full-width characters outside of this 15-
  * character alphabet (at the cost of an extra 8-bits per full-width character), and by stripping
- * out unnecessary comments, the end result is gcode which is roughly half the original size.
+ * out unnecessary comments, the end result is G-code which is roughly half the original size.
  *
  * Why did I do this? I noticed micro-stuttering and other data-bottleneck issues while printing
  * objects with high curvature, especially at high speeds. There is also the issue of the limited

Marlin/src/feature/mmu/mmu2-serial-protocol.md

@@ -51,7 +51,7 @@ When done, the MMU sends
 
 - MMU => 'ok\n'
 
-We don't wait for a response here but immediately continue with the next gcode which should
+We don't wait for a response here but immediately continue with the next G-code which should
 be one or more extruder moves to feed the filament into the hotend.
 
 

Marlin/src/feature/mmu/mmu2.cpp

@@ -939,7 +939,7 @@ bool MMU2::load_filament_to_nozzle(const uint8_t index) {
  * Load filament to nozzle of multimaterial printer
  *
  * This function is used only after T? (user select filament) and M600 (change filament).
- * It is not used after T0 .. T4 command (select filament), in such case, gcode is responsible for loading
+ * It is not used after T0 .. T4 command (select filament), in such case, G-code is responsible for loading
  * filament to nozzle.
  */
 void MMU2::load_to_nozzle() {