deprecations: replace all TBDs with 0.31.0

We accidentally released 0.30.0 and 0.31.0 with "future" deprecations.

Most users will not see these since the lint for them is different from
the normal deprecation warning (and it's undocumented except to say that
we "should not use" future deprecations, even though it works and there
is no alternative).

Somewhat fortunately, in 0.30.x we messed up the deprecations and
provided an inconsistent and weird API to replace the old functions. But
because we messed up the deprecation messages, we can pretend we didn't
do it and just mark the deprecations as having started in 0.31.x

Author: apoelstra

src/ecdh.rs

@@ -64,7 +64,7 @@ impl SharedSecret {
     pub fn from_bytes(bytes: [u8; SHARED_SECRET_SIZE]) -> SharedSecret { SharedSecret(bytes) }
 
     /// Creates a shared secret from `bytes` slice.
-    #[deprecated(since = "TBD", note = "Use `from_bytes` instead.")]
+    #[deprecated(since = "0.31.0", note = "Use `from_bytes` instead.")]
     #[inline]
     pub fn from_slice(bytes: &[u8]) -> Result<SharedSecret, Error> {
         match bytes.len() {

src/key.rs

@@ -220,7 +220,7 @@ impl SecretKey {
     /// use secp256k1::SecretKey;
     /// let sk = SecretKey::from_slice(&[0xcd; 32]).expect("32 bytes, within curve order");
     /// ```
-    #[deprecated(since = "TBD", note = "Use `from_byte_array` instead.")]
+    #[deprecated(since = "0.31.0", note = "Use `from_byte_array` instead.")]
     #[inline]
     pub fn from_slice(data: &[u8]) -> Result<SecretKey, Error> {
         match <[u8; constants::SECRET_KEY_SIZE]>::try_from(data) {
@@ -861,7 +861,7 @@ impl Keypair {
     ///
     /// [`Error::InvalidSecretKey`] if the slice is not exactly 32 bytes long,
     /// or if the encoded number is an invalid scalar.
-    #[deprecated(since = "TBD", note = "Use `from_seckey_byte_array` instead.")]
+    #[deprecated(since = "0.31.0", note = "Use `from_seckey_byte_array` instead.")]
     #[inline]
     pub fn from_seckey_slice<C: Signing>(
         secp: &Secp256k1<C>,
@@ -1240,7 +1240,7 @@ impl XOnlyPublicKey {
     ///
     /// Returns [`Error::InvalidPublicKey`] if the length of the data slice is not 32 bytes or the
     /// slice does not represent a valid Secp256k1 point x coordinate.
-    #[deprecated(since = "TBD", note = "Use `from_byte_array` instead.")]
+    #[deprecated(since = "0.31.0", note = "Use `from_byte_array` instead.")]
     #[inline]
     pub fn from_slice(data: &[u8]) -> Result<XOnlyPublicKey, Error> {
         match <[u8; constants::SCHNORR_PUBLIC_KEY_SIZE]>::try_from(data) {

src/lib.rs

@@ -256,7 +256,7 @@ impl Message {
     ///
     /// [secure signature]: https://twitter.com/pwuille/status/1063582706288586752
     #[inline]
-    #[deprecated(since = "TBD", note = "use from_digest instead")]
+    #[deprecated(since = "0.31.0", note = "use from_digest instead")]
     pub fn from_digest_slice(digest: &[u8]) -> Result<Message, Error> {
         Ok(Message::from_digest(digest.try_into().map_err(|_| Error::InvalidMessage)?))
     }

src/schnorr.rs

@@ -78,7 +78,7 @@ impl Signature {
     pub fn from_byte_array(sig: [u8; constants::SCHNORR_SIGNATURE_SIZE]) -> Self { Self(sig) }
 
     /// Creates a `Signature` directly from a slice.
-    #[deprecated(since = "TBD", note = "Use `from_byte_array` instead.")]
+    #[deprecated(since = "0.31.0", note = "Use `from_byte_array` instead.")]
     #[inline]
     pub fn from_slice(data: &[u8]) -> Result<Signature, Error> {
         match data.len() {
@@ -92,7 +92,7 @@ impl Signature {
     }
 
     /// Returns a signature as a byte array.
-    #[deprecated(since = "0.30.0", note = "Use `to_byte_array` instead.")]
+    #[deprecated(since = "0.31.0", note = "Use `to_byte_array` instead.")]
     pub fn serialize(&self) -> [u8; constants::SCHNORR_SIGNATURE_SIZE] { self.0 }
 
     /// Returns a signature as a byte array.