Fixed exception handler order

[bespaltovyj]

Hi, I fixed a bug due to which the documentation incorrectly displayed information obtained from the ExceptionHandler.
The problem was when there were 2 exception handlers (controller - local and global).

The documentation displayed information from the global, but in the Spring, the priority is higher for the local.

The problem was in the method AbstractOpenApiResource#getOpenApi. It him combined information about the 'Exception Handler' from the ControllerAdvice and from the controller. But HashMap was used as a container for which the order is not guaranteed.

I changed the container type to LinkedHashMap.

An exampleof a simple application in which you can check the issue

[bnasslahsen]

@bespaltovyj,

Agree for the fix !
Your branch contains conflicting changes.
You should synchronize with master and resolve the conflicts before proposing the PR.

[bespaltovyj]

@bnasslahsen fixed.
we just made changes at the same time

[bnasslahsen]

@bespaltovyj,

Perfect!
Thank you for your contribution to the project👍