[fixes #1498] Respect @Tolerate when using @Singular

[erikhofer]

This fixes #1498 and provides a solution to #1841.

import java.util.List;

import lombok.Builder;
import lombok.Singular;
import lombok.experimental.Tolerate;

@Builder
public class Foo {
	
	public static class FooBuilder {
		
		@Tolerate
		public FooBuilder bar(Integer i) {
			bar(i.toString());
			return this;
		}
	}
	
	@Singular
	private final List<String> bars;
}

This code currently produces the following error: Manually adding a method that @Singular @Builder would generate is not supported. If you want to manually manage the builder aspect for this field/parameter, don't use @Singular.

With this fix, it is possible to manually suppress this error with @Tolerate. It enables adding convenience methods with the same name as the generated methods.

[rzwitserloot]

Hmm, I'm not sure we want to allow this, but I'm having a hard time coming up with arguments that sound good. I dislike having to trust my gut if my brain can't come up with objective reasons.

Hey @rspilker 's gut and brain, how do you two feel about this?

[Rawi01]

@Tolerate documentation:

Put on any method or constructor to make lombok pretend it doesn't exist, i.e., to generate a method which would otherwise be skipped due to possible conflicts.

I think it is reasonable to assume that someone tries to add this annotation and I also don't know a reason why it should not work. If we add this I would propose to also change the error message e.g. or add the experimental @Tolerate annotation to your method. If we don't allow this we should update the @Tolerate documentation