Add spellcheck to markdown

[Hackerman342]

I've noticed a lot of typos in our documentation that should be fixed, so I added a spellcheck to the pre-commit config. Unfortunately we have a lot of "typos" that are not actually typos. For instance:

✗ /home/kyle/farm-ng/amiga-dev-kit/circuitpy/lib/farm_ng/utils/can.py 542 ms
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Typos: 19
1. stderr (1:17, count: 3)
2. canio (4:6, count: 6, suggest: Casio, Canada)
3. digitalio (5:6, suggest: digitalis, digital)
4. DigitalInOut (5:23, count: 3, suggest: Digital In Out)
5. BoardType (8:22, count: 5, suggest: Board Type)
6. def (12:1, count: 2)
7. 250K (13:88)
8. DISPV0 (17:38)
9. rx (18:26, count: 6)
10. PB13 (18:33)
11. tx (18:39, count: 6)
12. PB14 (18:46)
13. baudrate (18:52, count: 6)
14. elif (19:5, count: 2, suggest: elite)
15. M4 (19:42)
16. RX (20:39, count: 2)
17. TX (20:56, count: 2, suggest: T)
18. circuitpython (30:32, suggest: circuit python)
19. hasattr (34:8, count: 2)
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✗ /home/kyle/farm-ng/amiga-dev-kit/website/docs/tutorials/introduction/02_template_overview.md 299 ms
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Typos: 11
1. then kivy (45:111, suggest: thank ivy)
2. Kv (77:39)
3. UI (107:128)
4. args (count: 4, suggest: arms)
5. async (suggest: sync)
6. func (suggest: funk)
7. kivy (count: 22, suggest: ivy, Kevin, kitty, kiddy)
8. Kivy (suggest: Ivy, Kiev, Kitty)
9. kv
10. RelativeLayout (suggest: Relative Layout)
11. TemplateApp (suggest: Template App)
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✗ /home/kyle/farm-ng/amiga-dev-kit/website/docs/examples/import_log_file/README.md 240 ms
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Typos: 9
1. Congrats (40:1)
2. yyyy (80:1)
3. mm (80:6, count: 2)
4. dd (80:9, suggest: d)
5. hh (80:12, suggest: h)
6. ss (80:18, suggest: s)
7. msmsms (80:21)
8. hostname (80:33)
9. xxxx (80:42, suggest: XXX)

Capitalization: 1
1. ssh (count: 4, suggest: SSH)
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@edgarriba any thoughts on what we should do here.

For reference, the hook I used:

  - repo: https://github.com/hcodes/yaspeller
    rev: master
    hooks:
      - id: yaspeller