Fixed G-code (#4488)

* Fixed G-code

- Changed from `data` to `programming` -> CNC Programmers create gcode files that instruct machines where to move and what to do
- Gave a color (#ff4d6b)
- Added a commonly used file type for CNC programming (.mpf)

* Updated because mpf isn't as widely used as .cnc

cnc is a more widely used file extension than mpf is

* added sample cnc program

Sample CNC program for linguist

* Fixed color code and alphabetized file types

lib/linguist/languages.yml

@@ -1465,9 +1465,11 @@ Frege:
   ace_mode: haskell
   language_id: 116
 G-code:
-  type: data
+  type: programming
+  color: "#D08CF2"
   extensions:
   - ".g"
+  - ".cnc"
   - ".gco"
   - ".gcode"
   tm_scope: source.gcode