Add new features to "Insert New Chart"

[Wemmy0]

Minor change to add the line of best fit function into the 'Insert New Chart' form.

It's a minor change so possibly it can wait for the next version?

[netlify[bot]]

✅ Deploy Preview for obsidiancharts canceled.

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🔨 Latest commit	a987a8a27dcceac9a031b0bb8534dd66fb2d26c0
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[Wemmy0]

I've added the bestFit modifiers to the modifiers section in the documentation and updated the README.md to represent the updated documentation.

[Wemmy0]

Here's the final (apart from the changed version number woops): obsidian-charts.zip

[phibr0]

Thanks a lot!