Fix documentation for configuration of NoHandlerFoundAdviceTrait with Spring Boot >= 2.4.0

[markuswaidhofer]

Description

In the readme file, section configuration, it is documented which Spring Boot properties need to be set to make the NoHandlerFoundAdviceTrait work:

spring:
  resources:
    add-mappings: false
  mvc:
    throw-exception-if-no-handler-found: true

Starting with Spring Boot 2.4.0, spring.resources.* properties were moved to spring.web.resources.*: spring-projects/spring-boot#23917

The documentation should be updated to reflect this change (ideally mention different properties based on Spring boot versions).

I ran into this issue when upgrading Spring boot. Moving the property to spring.web.resources.add-mappings made NoHandlerFoundAdviceTrait work again.

I double checked this with the reference documentation:

• 2.3.x - property was named spring.resources.add-mappings
• 2.4.0 - property renamed to spring.web.resources.add-mappings

Possible Fix

Update documentation to mention that Spring boot >= 2.4.0 requires these properties:

spring:
  web:
    resources:
      add-mappings: false
  mvc:
    throw-exception-if-no-handler-found: true

I am happy to help here and make a PR if this is fine (first time contributer here 👋).