Add docs so far on the allowInClassWithAttributes because the rest is…

… not implemented yet

docs/allow-in-class-with-attributes.md

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+## Allow in class with given attributes
+
+It is possible to allow a previously disallowed function, method call or an attribute usage when done in a class with specified attributes.
+You can use the `allowInClassWithAttributes` configuration option.
+
+For example, if you'd have a configuration like this:
+
+```neon
+parameters:
+    disallowedMethodCalls:
+        -
+            method: 'PotentiallyDangerous\Logger::log()'
+            allowInClassWithAttributes:
+                - MyAttribute
+```
+
+Then the `log()` call would be allowed in a class that would look like this, note the attribute added on the class:
+
+```php
+#[MyAttribute]
+class Foo
+{
+    public function bar(): void
+    {
+        $this->dangerousLogger->log('something');
+    }
+}
+```
+
+On the other hand, if you need to disallow a method call, a function call, or an attribute usage only when present in a method from a class with a given attribute,
+use `allowExceptInClassWithAttributes` (or the `disallowInClassWithAttributes` alias):
+
+```neon
+parameters:
+    disallowedMethodCalls:
+        -
+            method: 'PotentiallyDangerous\Logger::log()'
+            allowExceptInClassWithAttributes:
+                - SomeAttribute
+```
+
+The `log()` method call would be allowed in the following class:
+
+```php
+class Foo
+{
+    public function bar(): void
+    {
+        $this->dangerousLogger->log('something');
+    }
+}
+```
+
+It would be disallowed in this class and in this class only because it has the `SomeAttribute` attribute:
+
+```php
+#[SomeAttribute]
+class Foo
+{
+    public function bar(): void
+    {
+        $this->dangerousLogger->log('something');
+    }
+}
+```
+
+The attribute names in the _allow_ directives support [fnmatch()](https://www.php.net/function.fnmatch) patterns.