Adjust README headings

README.adoc

@@ -159,13 +159,13 @@ image::./docs/transparent-color.png[]
 
 To see what's possible with colors, have a look at the rainbow example in the bad examples below.
 
-== Types
+=== Types
 
 In order to create certain types of QR codes, you can may want to use the following utils.
 
 Please see https://github.com/SimonScholz/qr-code-with-logo/blob/main/kotlin-sample/src/main/kotlin/io/github/simonscholz/QrCodeTypesMain.kt[`kotlin-sample` module] or https://github.com/SimonScholz/qr-code-with-logo/blob/main/java-sample/src/main/java/io/github/simonscholz/QrCodeTypesMain.java[`java-sample` module] to use these types and run the samples.
 
-=== Simple types
+==== Simple types
 
 ```java
 String url = SimpleTypes.url("https://simonscholz.github.io/");
@@ -181,7 +181,7 @@ String sms = SimpleTypes.sms("+49 176 12345678", "Hello, this is a test SMS");
 
 These String values can be used to create a QR code.
 
-== More complex types
+==== More complex types
 
 VEVENT type: