docs: Improve SpringQueryMap documentation

[bombo-dev]

Problem

When using the @SpringQueryMap annotation, it was difficult to discover the existence of the QueryMapEncoder class.
The reference path is as follows:
@SpringQueryMap -> @QueryMap -> @Param Usage All

Additionally, when using @SpringQueryMap, the default injected implementation is FieldQueryMapEncoder.
However, in FeignClientsConfiguration, the injected bean can change depending on the @ConditionalOnClass condition.

@Bean
@ConditionalOnClass(name = "org.springframework.data.domain.Pageable")
@ConditionalOnMissingBean
public QueryMapEncoder feignQueryMapEncoderPageable() {
	PageableSpringQueryMapEncoder queryMapEncoder = new PageableSpringQueryMapEncoder();
	if (springDataWebProperties != null) {
		queryMapEncoder.setPageParameter(springDataWebProperties.getPageable().getPageParameter());
		queryMapEncoder.setSizeParameter(springDataWebProperties.getPageable().getSizeParameter());
		queryMapEncoder.setSortParameter(springDataWebProperties.getSort().getSortParameter());
	}
	return queryMapEncoder;
}

Although FieldQueryMapEncoder is marked as deprecated in QueryMapEncoder, it still functions as the default implementation.

Solution

I have explicitly specified this behavior in the annotation documentation.
I encountered this issue while debugging, and it took me a long time to identify the cause.
By adding this information, I hope others can find the relevant details more quickly.

Consideration

I initially considered adding the note:

"The default implementation is FieldQueryMapEncoder, but it can change to PageableSpringQueryMapEncoder depending on the conditions."

However, since this behavior is subject to change, I decided not to include it.
If necessary, I am open to adding this detail.

related to #1163