public <A extends Annotation> void registerBuilderModifier(
            final @NonNull Class<A> annotation,
            final @NonNull BuilderModifier<A, C> builderModifier
    ) {
        this.builderModifiers.put(annotation, builderModifier);
    }
Register a builder modifier for a specific annotation. The builder modifiers are
allowed to act on a {@link org.incendo.cloud.Command.Builder} after all arguments have been added
to the builder. This allows for modifications of the builder instance before
the command is registered to the command manager.

@param annotation      Annotation (class) that the builder modifier reacts to
@param builderModifier Modifier that acts on the given annotation and the incoming builder. Command builders
                       are immutable, so the modifier should return the instance of the command builder that is
                       returned as a result of any operation on the builder
@param <A>             Annotation type
cloud-annotations/src/main/java/org/incendo/cloud/annotations/AnnotationParser.java