[DOCS] remove the $ symbol from the code snippets in installation.md

[kaizakin]

Is there an existing issue for this?

• I have searched the existing issues

Kubernetes Version

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Shipwright Version

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Current Behavior

the $ symbol in docs/getting-started/installation.md in website breaks the click to copy flow like this

causing users to manually select and copy commands, in that case it makes the click to copy button useless

removing that would be better

Expected Behavior

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Steps To Reproduce

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Anything else?

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