Improve code samples in README.md

Author: spawnia

README.md

@@ -5,6 +5,7 @@ A collection of custom scalar types for usage with https://github.com/webonyx/gr
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+
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@@ -47,8 +48,6 @@ The quickest way to define a custom scalar is the `make` factory method. Just pr
 a name and a regular expression and you will receive a ready-to-use custom regex scalar.
 
 ```php
-<?php
-
 use MLL\GraphQLScalars\Regex;
 
 $hexValue = Regex::make(
@@ -61,8 +60,6 @@ $hexValue = Regex::make(
 You may also define your regex scalar as a class.
 
 ```php
-<?php
-
 use MLL\GraphQLScalars\Regex;
 
 // The name is implicitly set through the class name here
@@ -78,7 +75,7 @@ A hexadecimal color is specified with: `#RRGGBB`, where `RR` (red), `GG` (green)
 are hexadecimal integers between `00` and `FF` specifying the intensity of the color.
 DESCRIPTION;
 
-    public static function regex() : string
+    public static function regex(): string
     {
         return '/^#?([a-f0-9]{6}|[a-f0-9]{3})$/';
     }
@@ -94,14 +91,12 @@ All you have to specify is a function that checks if the given string is valid.
 Use the factory method `make` to generate an instance on the fly.
 
 ```php
-<?php
-
 use MLL\GraphQLScalars\StringScalar;
 
 $coolName = StringScalar::make(
     'CoolName',
     'A name that is most definitely cool.',
-    function(string $name): bool {
+    static function (string $name): bool {
         return in_array($name, [
            'Vladar',
            'Benedikt',