fix redirect_stdio rules on nightly again (#421)

These were broken by JuliaLang/julia#37978 again.

Author: simeonschaub

Project.toml

@@ -1,6 +1,6 @@
 name = "ChainRules"
 uuid = "082447d4-558c-5d27-93f4-14fc19e9eca2"
-version = "0.7.69"
+version = "0.7.70"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"

src/rulesets/Base/nondiff.jl

@@ -316,9 +316,7 @@ VERSION >= v"1.4" && @non_differentiable only(::Char)
 @non_differentiable readuntil(::IO, ::AbstractString)
 @non_differentiable realpath(::AbstractString)
 if isdefined(Base, :redirect_stdio)
-    @non_differentiable (::Base.redirect_stdio)(
-        ::Union{IOStream, Base.LibuvStream, Base.DevNull, Base.AbstractPipe},
-    )
+    @non_differentiable Base.redirect_stdio(::Any)
 else
     @non_differentiable redirect_stderr(
         ::Union{IOStream, Base.LibuvStream, Base.DevNull, IOContext},