[AutoDiff] make differentiable array ops inlinable (swiftlang#31704)

Author: marcrasi

stdlib/public/Differentiation/ArrayDifferentiation.swift

@@ -262,6 +262,7 @@ extension Array where Element: Differentiable {
 //===----------------------------------------------------------------------===//
 
 extension Array where Element: Differentiable {
+  @inlinable
   @differentiable(wrt: (self, initialResult))
   public func differentiableReduce<Result: Differentiable>(
     _ initialResult: Result,
@@ -270,7 +271,7 @@ extension Array where Element: Differentiable {
     reduce(initialResult, nextPartialResult)
   }
 
-  @usableFromInline
+  @inlinable
   @derivative(of: differentiableReduce)
   internal func _vjpDifferentiableReduce<Result: Differentiable>(
     _ initialResult: Result,
@@ -310,14 +311,15 @@ extension Array where Element: Differentiable {
 }
 
 extension Array where Element: Differentiable {
+  @inlinable
   @differentiable(wrt: self)
   public func differentiableMap<Result: Differentiable>(
     _ body: @differentiable (Element) -> Result
   ) -> [Result] {
     map(body)
   }
 
-  @usableFromInline
+  @inlinable
   @derivative(of: differentiableMap)
   internal func _vjpDifferentiableMap<Result: Differentiable>(
     _ body: @differentiable (Element) -> Result