style: correct keybinding name and improve formatting in default_conf…

…ig.nu (nushell#11889)

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# Description
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This PR addresses a minor mismatch in a keybinding name within the
`default_config.nu` file. Additionally, it applies formatting for
consistency.
# User-Facing Changes
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helps us keep track of breaking changes. -->

# Tests + Formatting
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# After Submitting
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