Revise the chapter on missing macro fragment specifiers

Now that this is a hard error in all editions, let's adjust the text a
bit to make it clear what behavior is current and what is historical.

Author: traviscross

src/rust-2024/missing-macro-fragment-specifiers.md

@@ -1,14 +1,14 @@
 # Missing macro fragment specifiers
 
-> **NOTE**: `missing_fragment_specifier` was originally made a hard error only for the 2024 Edition. In the time since this edition was released, the lint has been made into a hard error for all editions.
+> **NOTE**: This was originally made a hard error only for the 2024 Edition. In Rust 1.89, released after Rust 2024, the lint was made into a hard error in all editions.
 
 ## Summary
 
 - The `missing_fragment_specifier` lint is now a hard error.
 
 ## Details
 
-The `missing_fragment_specifier` lint detects a situation when an **unused** pattern in a `macro_rules!` macro definition has a meta-variable (e.g. `$e`) that is not followed by a fragment specifier (e.g. `:expr`). This is now a hard error in the 2024 Edition.
+The `missing_fragment_specifier` lint detected a situation when an **unused** pattern in a `macro_rules!` macro definition had a meta-variable (e.g. `$e`) that was not followed by a fragment specifier (e.g. `:expr`). This was made into a hard error in the 2024 Edition.
 
 ```rust,compile_fail
 macro_rules! foo {
@@ -21,16 +21,10 @@ fn main() {
 }
 ```
 
-Calling the macro with arguments that would match a rule with a missing specifier (e.g., `foo!($name)`) is a hard error in all editions. However, simply defining a macro with missing fragment specifiers is not, though we did add a lint in Rust 1.17.
-
-We'd like to make this a hard error in all editions, but there would be too much breakage right now. So we're starting by making this a hard error in Rust 2024.[^future-incompat]
-
-[^future-incompat]: The lint is marked as a "future-incompatible" warning to indicate that it may become a hard error in all editions in a future release. See [#40107] for more information.
-
-[#40107]: https://github.com/rust-lang/rust/issues/40107
+Calling the macro with arguments that would match a rule with a missing specifier (e.g., `foo!($name)`) was a hard error in all editions. However, simply defining a macro with missing fragment specifiers was not, though we did add a lint in Rust 1.17.
 
 ## Migration
 
-To migrate your code to the 2024 Edition, remove the unused matcher rule from the macro. The `missing_fragment_specifier` lint is on by default in all editions, and should alert you to macros with this issue.
+To migrate your code to the 2024 Edition, remove the unused matcher rule from the macro.
 
-There is no automatic migration for this change. We expect that this style of macro is extremely rare. The lint has been a future-incompatibility lint since Rust 1.17, a deny-by-default lint since Rust 1.20, and since Rust 1.82, it has warned about dependencies that are using this pattern.
+There is no automatic migration for this change. We expect that this style of macro is extremely rare. The lint was a future-incompatibility lint since Rust 1.17, a deny-by-default lint since Rust 1.20, since Rust 1.82 it warned about dependencies using this pattern, and in Rust 1.89 it became a hard error.