enable new Float16 methods for sinh and cbrt

From #39432 and #39441, these were still using their old definition due
to method overwriting.

base/math.jl

@@ -1195,7 +1195,7 @@ include("special/log.jl")
 
 # Float16 definitions
 
-for func in (:sin,:cos,:tan,:asin,:acos,:atan,:sinh,:cosh,:tanh,:asinh,:acosh,
+for func in (:sin,:cos,:tan,:asin,:acos,:atan,:cosh,:tanh,:asinh,:acosh,
              :atanh,:log,:log2,:log10,:sqrt,:lgamma,:log1p)
     @eval begin
         $func(a::Float16) = Float16($func(Float32(a)))
@@ -1209,7 +1209,6 @@ end
 
 
 atan(a::Float16,b::Float16) = Float16(atan(Float32(a),Float32(b)))
-cbrt(a::Float16) = Float16(cbrt(Float32(a)))
 sincos(a::Float16) = Float16.(sincos(Float32(a)))
 
 for f in (:sin, :cos, :tan, :asin, :atan, :acos,