Docs: Update usage for generatePassword() in README

[Greenheart]

See updated docstring here:

pagecrypt/src/core.ts

Lines 60 to 82 in c850468

	/**
	* Encrypt an HTML string with a given password.
	* The resulting page can be viewed and decrypted by opening the output HTML file in a browser, and entering the correct password.
	*
	* @param {string} inputHTML The HTML string to encrypt.
	* @param {string} password The password used to encrypt + decrypt the content.
	* @param {number} iterations The number of iterations to derive the key from the password.
	* @returns A promise that will resolve with the encrypted HTML content
	*/
	export async function encryptHTML(
	inputHTML: string,
	password: string,
	iterations: number = 2e6,
	) {
	return (decryptTemplate as string).replace(
	/<!--ENCRYPTED PAYLOAD-->/,
	`<pre class="hidden" data-i="${iterations.toExponential()}">${await getEncryptedPayload(
	inputHTML,
	password,
	iterations,
	)}</pre>`,
	)
	}

It's also important to enforce the max length of the character set = 256 characters. This should likely be in the docstring too, so we could update generatePassword() too to reflect that.

[Greenheart]

Will be resolved in the next release