Typo in no-negation-in-equality-check's message

[incendial]

Hi, it looks like there is a typo in no-negation-in-equality-check's message https://github.com/sindresorhus/eslint-plugin-unicorn/blob/main/rules/no-negation-in-equality-check.js#L15

const messages = {
  [MESSAGE_ID_ERROR]: 'Negated expression in not allowed in equality check.', // Should be "is not" instead of "in not"
  [MESSAGE_ID_SUGGESTION]: 'Switch to \'{{operator}}\' check.',
};

[fregante]

@incendial Thanks! Fixed