Adding section about mt (#807)

Co-authored-by: Johannes Müller <[email protected]>

_releases/2024-07-09-1.13.0-released.md

@@ -17,6 +17,13 @@ This release includes [XX changes since 1.12.2](https://github.com/crystal-lang/
 by ZZZ contributors. We thank all the contributors for all the effort put into
 improving the language! ❤️
 
+## Advances in multi-threading support
+
+As part of the [project to improve multi-threading support](/2024/02/09/84codes-manas-mt) with the help of [84codes], 
+this release includes several improvements and refactors related to concurrency and the event loop. So far, these have been mostly internal changes with minor relevance from a user's point of view. We expect more significant changes in the next release.
+
+A preview of the upcoming execution context ([RFC](https://github.com/crystal-lang/rfcs/pull/2)) is available as a standalone shard: [`ysbaddaden/execution_context`](https://github.com/ysbaddaden/execution_context). It's available for testing by eager developers. This library is expected to be part of the compiler once we are certain it's ready.  We're still ironing it, so bugs are expected, and reports very much welcomed!
+
 ## Changes
 
 Below we list the most remarkable changes in the language, compiler and stdlib.
@@ -103,7 +110,7 @@ sched.enqueue 70569399831716 thread=0x7f48d7dc9740:? fiber=0x7f48d7cd0f00:main f
 Hello World
 ```
 
-_Thanks [@ysbaddaden] and [84codes](https://www.84codes.com/)_
+_Thanks [@ysbaddaden] and [84codes]_
 
 ### `WaitGroup`
 
@@ -131,33 +138,34 @@ wg.wait
 ```
 
 _Thanks [@ysbaddaden] and [84codes](https://www.84codes.com/)_
+
 ### Compiler
 
-* New compiler flags `-Os` and `-Oz` to optimize binary size ([#14463](https://github.com/crystal-lang/crystal/pull/14463)).
+- New compiler flags `-Os` and `-Oz` to optimize binary size ([#14463](https://github.com/crystal-lang/crystal/pull/14463)).
 
   _Thanks [@ysbaddaden]_
 
-* Basic compiler support for AVR architecture (Arduino) ([#14393](https://github.com/crystal-lang/crystal/pull/14393)).
+- Basic compiler support for AVR architecture (Arduino) ([#14393](https://github.com/crystal-lang/crystal/pull/14393)).
 
   _Thanks [@ysbaddaden]_
 
-* Do not strip the macOS target triple ([#14466](https://github.com/crystal-lang/crystal/pull/14466)).
+- Do not strip the macOS target triple ([#14466](https://github.com/crystal-lang/crystal/pull/14466)).
 
   _Thanks [@hovsater]_
 
 ### Misc
 
-* Add UUID v7 implementation ([#14732](https://github.com/crystal-lang/crystal/pull/14732))
+- Add UUID v7 implementation ([#14732](https://github.com/crystal-lang/crystal/pull/14732))
 
   _Thanks [@jgaskins]_
 
-* New method: `Array#insert_all` ([#14486](https://github.com/crystal-lang/crystal/pull/14486))
+- New method: `Array#insert_all` ([#14486](https://github.com/crystal-lang/crystal/pull/14486))
 
   _Thanks [@summer-alice]_
 
 ## Deprecations
 
-* `File.readable?`, `.writable?`, `.executable?` are moved to `File::Info`. They are low-level methods and removing them from the prominent `File` namespace reduces potential for confusion. ([#14484](https://github.com/crystal-lang/crystal/pull/14484))
+- `File.readable?`, `.writable?`, `.executable?` are moved to `File::Info`. They are low-level methods and removing them from the prominent `File` namespace reduces potential for confusion. ([#14484](https://github.com/crystal-lang/crystal/pull/14484))
 
   _Thanks [@straight-shoota]_
 
@@ -182,3 +190,4 @@ _Thanks [@ysbaddaden] and [84codes](https://www.84codes.com/)_
 [@summer-alice]: https://github.com/summer-alice
 [@meatball133]: https://github.com/meatball133
 [@Hadeweka]: https://github.com/@Hadeweka
+[84codes]: https://www.84codes.com/