Bump Slang release version to v2025.14.2 to include a fix

The following commit on Slang Release v2025.14.1 causes a regression,
```
063cbeaae Initial copy elision pass (#8042)
```

v2025.14.2 fixed it with the following commit.
```
719772c Initial copy elision pass regression fix (#8126)
```

Author: jkwak-work

landing/siggraph-25/index.md

@@ -4,7 +4,7 @@
 
 This is the landing page for the SIGGRAPH 2025 Course "Introduction to Neural Shading". You will find source code and other accompanying materials with the course here as they become available.
 
-The latest release of Slang for SIGGRAPH can be found here https://github.com/shader-slang/slang/releases/tag/v2025.14.1
+The latest release of Slang for SIGGRAPH can be found here https://github.com/shader-slang/slang/releases/tag/v2025.14.2
 
 ## [Hands-On Class: Introduction to Slang](https://s2025.conference-schedule.org/?post_type=page&p=14&id=gensubcur_104&sess=sess287)