Fix cpu temp examples

[cyhyraethz]

Use - instead of _ for [sensor], as in #129

[JakeStanger]

Thanks for this, I'll merge this to sort the docs.

As per my comment in #129 I will probs eventually switch the names to use _`` instead of -` for consistency, but that will likely not be until I touch the other sys_info related issues.

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Please can you adhere to conventional commits for future contributions to ensure you're included in the changelog, as otherwise I have to amend this?