Make = and => optional in function declarations

[nrc]

Also makes return types use : and formats parameter and return types

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Name	Status	Preview	Updated (UTC)
modeling-app	✅ Ready (Inspect)	Visit Preview	Nov 26, 2024 3:56am

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 89.86486% with 15 lines in your changes missing coverage. Please review.

Project coverage is 86.16%. Comparing base (5424252) to head (5e58986).

Files with missing lines	Patch %	Lines
src/wasm-lib/kcl/src/unparser.rs	77.77%	14 Missing :warning:
src/wasm-lib/kcl/src/parser.rs	66.66%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #4577 +/- ## ========================================== - Coverage 86.17% 86.16% -0.01% ========================================== Files 80 80 Lines 29736 29824 +88 ========================================== + Hits 25624 25697 +73 - Misses 4112 4127 +15 ``` | [Flag](https://app.codecov.io/gh/KittyCAD/modeling-app/pull/4577/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=KittyCAD) | Coverage Δ | | |---|---|---| | [wasm-lib](https://app.codecov.io/gh/KittyCAD/modeling-app/pull/4577/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=KittyCAD) | `86.16% <89.86%> (-0.01%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=KittyCAD#carryforward-flags-in-the-pull-request-comment) to find out more.

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