Fix typos and add codespell pre-commit hook

[kianmeng]

PR Checklist

Please check if your PR fulfills the following requirements:

• I have read, and am following the Contributor guide
• I have read and understand the Code of Conduct

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Documentation content changes

What is the current behavior?

Issue Number: N/A

What is the new behavior?

Does this PR introduce a breaking change?

• Yes
• No

Other information

[sourcery-ai]

Sourcery Code Quality Report

❌  Merging this PR will decrease code quality in the affected files by 0.16%.

Quality metrics	Before	After	Change
Complexity	4.55 ⭐	4.63 ⭐	0.08 👎
Method Length	47.71 ⭐	47.66 ⭐	-0.05 👍
Working memory	3.86 ⭐	3.91 ⭐	0.05 👎
Quality	69.42% 🙂	69.26% 🙂	-0.16% 👎

Other metrics	Before	After	Change
Lines	829	827	-2

Changed files	Quality Before	Quality After	Quality Change
examples/demo.py	57.28% 🙂	57.28% 🙂	0.00%
gaphas/model.py	99.40% ⭐	99.40% ⭐	0.00%
gaphas/quadtree.py	76.96% ⭐	76.48% ⭐	-0.48% 👎
gaphas/solver/constraint.py	93.39% ⭐	93.39% ⭐	0.00%
gaphas/tool/hover.py	89.27% ⭐	89.27% ⭐	0.00%

Here are some functions in these files that still need a tune-up:

File	Function	Complexity	Length	Working Memory	Quality	Recommendation
examples/demo.py	create_window	13 🙂	851 ⛔		31.45% 😞	Try splitting into smaller methods
gaphas/quadtree.py	Quadtree.add	12 🙂	109 🙂	11 😞	54.39% 🙂	Extract out complex expressions
gaphas/quadtree.py	QuadtreeBucket.add	3 ⭐	169 😞	11 😞	56.14% 🙂	Try splitting into smaller methods. Extract out complex expressions
examples/demo.py	create_canvas	1 ⭐	267 ⛔	6 ⭐	62.56% 🙂	Try splitting into smaller methods
gaphas/quadtree.py	QuadtreeBucket.find_bucket	5 ⭐	91 🙂	10 😞	65.30% 🙂	Extract out complex expressions

Legend and Explanation

The emojis denote the absolute quality of the code:

• ⭐ excellent
• 🙂 good
• 😞 poor
• ⛔ very poor

The 👍 and 👎 indicate whether the quality has improved or gotten worse with this pull request.

---

Please see our documentation here for details on how these metrics are calculated.

We are actively working on this report - lots more documentation and extra metrics to come!

Help us improve this quality report!

[danyeaw]

Thanks @kianmeng for the updates and great idea to add the additional pre-commit hook!