Use AnnotationCallback instead of Nothing (#1139)

Co-authored-by: Ruslan Sadykov <41117501+rrsadykov@users.noreply.github.com>

Author: blegat

src/MOIcallbacks.jl

@@ -15,7 +15,7 @@ function MOI.set(model::Coluna.Optimizer, attr::MOI.LazyConstraintCallback, call
     return
 end
 
-function MOI.set(model::Coluna.Optimizer, ::BD.PricingCallback, ::Nothing)
+function MOI.set(model::Coluna.Optimizer, ::BD.PricingCallback, ::BD.AnnotationCallback)
     model.has_pricing_cb = true
     # We register the pricing callback through the annotations.
     return
@@ -232,4 +232,4 @@ function MOI.get(model::Optimizer, spid::BD.PricingSubproblemId{MathProg.Initial
     uid = getuid(callback_data.form)
     axis_index_value = model.annotations.ann_per_form[uid].axis_index_value
     return axis_index_value
-end
+end