Update 'README.md'

Fixed code blocks

README.md

@@ -30,17 +30,18 @@ Install using composer:
 You need a key for both generating and parsing tokens. Create a `JwtDerivedKey`
 or a `JwtPlaintextKey` and pass it to the `JwtToken` constructor:
 
+```php
 use NoccyLabs\SimpleJwt\Key\{JwtDerivedKey,JwtPlaintextKey}
 
 // Derive a key using secret and salt...
 $key = new JwtDerivedKey("secret", "salt");
 // ...or use a prepared plaintext key
 $key = new JwtPlaintextKey("This Should Be Binary Data..");
+```
 
 ### Generating tokens
 
-
+```php
-
 use NoccyLabs\SimpleJwt\JwtToken;
 
 $tok = new JwtToken($key);
@@ -48,12 +49,13 @@ or a `JwtPlaintextKey` and pass it to the `JwtToken` constructor:
 $tok->claims->add("some/claim/MaxItems", 8);
 
 $str = $tok->getSignedToken();
-
+```
 
 ### Parsing tokens
 
 Parsing is done by passing the raw token as the 2nd parameter
 
+```php
 use NoccyLabs\SimpleJwt\JwtToken;
 
 $str = "...received token...";
@@ -72,9 +74,11 @@ Parsing is done by passing the raw token as the 2nd parameter
 
 // You can also use valueOf() to return a default value if needed
 $val = $tok->claims->valueOf("some/claim/MaxItems", 64);
+```
 
 ### Validating tokens
 
+```php
 use NoccyLabs\SimpleJwt\Validator\JwtValidator;
 
 $validator = new JwtValidator();
@@ -93,3 +97,4 @@ Parsing is done by passing the raw token as the 2nd parameter
 catch (JwtValidatorException $e) {
     // validation failed
 }
+```