crypto/rsa: remove deprecation markers for multiprime RSA support

These should be marked deprecated, but that needs a
(likely quick) proposal review.

The proposal is #56921.

Change-Id: I013a913a7f5196a341e2dd5f49c2687c26ee8331
Reviewed-on: https://go-review.googlesource.com/c/go/+/453257
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Roland Shoemaker <roland@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>

src/crypto/rsa/rsa.go

@@ -204,8 +204,8 @@ type PrecomputedValues struct {
 	// differently in PKCS #1 and interoperability is sufficiently
 	// important that we mirror this.
 	//
-	// Deprecated: these values are still filled in by Precompute for
-	// backwards compatibility, but are not used. Multi-prime RSA is very rare,
+	// Note: these values are still filled in by Precompute for
+	// backwards compatibility but are not used. Multi-prime RSA is very rare,
 	// and is implemented by this package without CRT optimizations to limit
 	// complexity.
 	CRTValues []CRTValue
@@ -278,7 +278,7 @@ func GenerateKey(random io.Reader, bits int) (*PrivateKey, error) {
 // This package does not implement CRT optimizations for multi-prime RSA, so the
 // keys with more than two primes will have worse performance.
 //
-// Deprecated: The use of this function with a number of primes different from
+// Note: The use of this function with a number of primes different from
 // two is not recommended for the above security, compatibility, and performance
 // reasons. Use GenerateKey instead.
 //