feat: Update index.php to allow users to just copy paste the line on the config.php file

The initial syntax used double quotes and two points which is not the correct syntax in the config.php file instead of simple quote and "=>".
This proposition to allow users to just copy paste the line into their config.php file

Signed-off-by: waazdakka <raphael.piedallu@live.com>

Author: waazdakka

index.php

@@ -1987,7 +1987,7 @@ public function isAuthenticated(): bool {
 				<p>To login you need to provide the unhashed value of "updater.secret" in your config file.</p>
 				<p>If you don't know that value, you can access this updater directly via the Nextcloud admin screen or generate
 				your own secret:</p>
-				<code>php -r '$password = trim(shell_exec("openssl rand -base64 48"));if(strlen($password) === 64) {$hash = password_hash($password, PASSWORD_DEFAULT) . "\n"; echo "Insert as \"updater.secret\": ".$hash; echo "The plaintext value is: ".$password."\n";}else{echo "Could not execute OpenSSL.\n";};'</code>
+				<code>php -r '$password = trim(shell_exec("openssl rand -base64 48"));if(strlen($password) === 64) {$hash = password_hash($password, PASSWORD_DEFAULT); echo "Insert this line in your config.php: \n\n'"  'updater.secret' => '"'.$hash'"',\n\n"'"; echo "The plaintext value is: ".$password."\n";;}else{echo "Could not execute OpenSSL.\n";};'</code>
 				<form method="post" name="login">
 					<fieldset>
 						<input type="password" name="updater-secret-input" value=""