Add a graceful deprecation

Author: mbauman

base/deprecated.jl

@@ -1514,6 +1514,10 @@ end
 @deprecate_binding uninitialized undef
 @deprecate_binding Uninitialized UndefInitializer
 
+# remove broadcast MatrixStyle and VectorStyle (Issue #26430)
+@eval Broadcast Base.@deprecate_binding MatrixStyle DefaultArrayStyle{2} false
+@eval Broadcast Base.@deprecate_binding VectorStyle DefaultArrayStyle{1} false
+
 @deprecate showcompact(x) show(IOContext(stdout, :compact => true), x)
 @deprecate showcompact(io, x) show(IOContext(io, :compact => true), x)
 @deprecate sprint(::typeof(showcompact), args...) sprint(show, args...; context=:compact => true)