Warn on future deprecations

We use `TBD` in our `deprecated` string and it was discovered that there
is an exception on this string so as not to warn because it is used
internally by the Rust language. However there is a special lint to
enable warnings, lets use it.

Add `#![warn(deprecated_in_future)]` to the coding conventions section
of all crates except `fuzz`.

addresses/src/lib.rs

@@ -16,6 +16,7 @@
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
 #![doc(test(attr(warn(unused))))]
 // Coding conventions.
+#![warn(deprecated_in_future)]
 #![warn(missing_docs)]
 // Exclude lints we don't think are valuable.
 #![allow(clippy::needless_question_mark)] // https://github.com/rust-bitcoin/rust-bitcoin/pull/2134

base58/src/lib.rs

@@ -12,6 +12,7 @@
 #![cfg_attr(bench, feature(test))]
 // Coding conventions.
 #![warn(missing_docs)]
+#![warn(deprecated_in_future)]
 #![doc(test(attr(warn(unused))))]
 // Instead of littering the codebase for non-fuzzing and bench code just globally allow.
 #![cfg_attr(fuzzing, allow(dead_code, unused_imports))]

bitcoin/src/lib.rs

@@ -30,6 +30,7 @@
 #![cfg_attr(bench, feature(test))]
 // Coding conventions.
 #![warn(missing_docs)]
+#![warn(deprecated_in_future)]
 #![doc(test(attr(warn(unused))))]
 // Instead of littering the codebase for non-fuzzing and bench code just globally allow.
 #![cfg_attr(fuzzing, allow(dead_code, unused_imports))]

hashes/src/lib.rs

@@ -56,6 +56,7 @@
 #![cfg_attr(bench, feature(test))]
 // Coding conventions.
 #![warn(missing_docs)]
+#![warn(deprecated_in_future)]
 #![doc(test(attr(warn(unused))))]
 // Instead of littering the codebase for non-fuzzing and bench code just globally allow.
 #![cfg_attr(hashes_fuzz, allow(dead_code, unused_imports))]

internals/src/lib.rs

@@ -10,6 +10,7 @@
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
 // Coding conventions.
 #![warn(missing_docs)]
+#![warn(deprecated_in_future)]
 #![doc(test(attr(warn(unused))))]
 // Exclude lints we don't think are valuable.
 #![allow(clippy::needless_question_mark)] // https://github.com/rust-bitcoin/rust-bitcoin/pull/2134

primitives/src/lib.rs

@@ -13,6 +13,7 @@
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
 // Coding conventions.
 #![warn(missing_docs)]
+#![warn(deprecated_in_future)]
 #![doc(test(attr(warn(unused))))]
 // Exclude lints we don't think are valuable.
 #![allow(clippy::needless_question_mark)] // https://github.com/rust-bitcoin/rust-bitcoin/pull/2134

units/src/lib.rs

@@ -8,6 +8,7 @@
 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
 // Coding conventions.
 #![warn(missing_docs)]
+#![warn(deprecated_in_future)]
 #![doc(test(attr(warn(unused))))]
 // Exclude lints we don't think are valuable.
 #![allow(clippy::needless_question_mark)] // https://github.com/rust-bitcoin/rust-bitcoin/pull/2134