docs: remove '$' from installation commands in Installation docs

[wo-o29]

🎯 Changes

• Removed unnecessary '$' from installation command lines in the Installation documentation.
• Made command lines consistent and easier to copy for users.

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• [X] I have followed the steps listed in the Contributing guide.
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Latest commit: fefc5d30a2e759c560cd46a8b55412422ec32f8f

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