Merge pull request #5655 from kenjis/update-internals.md

docs: update internals.md

Author: kenjis

contributing/internals.md

@@ -17,11 +17,9 @@ other core packages, you can create that in the constructor using the
 override that:
 
 ```php
-    public function __construct(Foo $foo=null)
+    public function __construct(?Foo $foo = null)
     {
-        $this->foo = $foo instanceOf Foo
-            ? $foo
-            : \Config\Services::foo();
+        $this->foo = $foo ?? \Config\Services::foo();
     }
 ```
 
@@ -75,7 +73,7 @@ package itself will need its own sub-namespace that collects all related
 files into one grouping, like `CodeIgniter\HTTP`.
 
 Files MUST be named the same as the class they hold, and they must match
-the Style Guide <./styleguide.md>, meaning CamelCase class and
+the [Style Guide](styleguide.md), meaning CamelCase class and
 file names. They should be in their own directory that matches the
 sub-namespace under the **system** directory.