Update slack.jl

Author: odow

src/Bridges/Constraint/bridges/slack.jl

@@ -124,8 +124,8 @@ end
 function MOI.get(
     model::MOI.ModelLike,
     a::Union{MOI.ConstraintDual,MOI.ConstraintDualStart},
-    bridge::_AbstractSlackBridge,
-)
+    bridge::_AbstractSlackBridge{T},
+) whhere {T}
     # The dual constraint on slack (since it is free) is
     # `-dual_slack_in_set + dual_equality = 0` so the two duals are
     # equal and we can return either one of them.