Replaces insecure HTTP URLs to the site in the given content, if configured to do so.

This function replaces all occurrences of the HTTP version of the site’s URL with its HTTPS counterpart, if
determined via {@see}.

function wp_replace_insecure_home_url( $content ) {
	if ( ! wp_should_replace_insecure_home_url() ) {
		return $content;
	}

	$https_url = home_url( '', 'https' );
	$http_url  = str_replace( 'https://', 'http://', $https_url );

	// Also replace potentially escaped URL.
	$escaped_https_url = str_replace( '/', '/', $https_url );
	$escaped_http_url  = str_replace( '/', '/', $http_url );

	return str_replace(
		array(
			$http_url,
			$escaped_http_url,
		),
		array(
			$https_url,
			$escaped_https_url,
		),
		$content
	);
}