Update 2025-04-15-ubuntu-mate-plucky-puffin.md: Kernel is 6.14 and not 6.15 (#185)

As Chris Guiver (@guiverc) has pointed out in 
https://ubuntu-mate.community/t/typo-in-ubuntu-mate-25-04-release-notes/29294

... the version of the Linux Kernel in Ubuntu MATE 25.04 ("Plucky Puffin") is 6.14 and not 6.15

Author: ricmarques

_posts/2025-04-15-ubuntu-mate-plucky-puffin.md

@@ -28,7 +28,7 @@ Here are the highlights of what's new in the Plucky Puffin release:
 
 ## Major Applications
 
-Accompanying **MATE Desktop** 🧉 and **Linux 6.15** 🐧 are **Firefox 137** 🔥🦊,
+Accompanying **MATE Desktop** 🧉 and **Linux 6.14** 🐧 are **Firefox 137** 🔥🦊,
 **Evolution 3.56** 📧, **LibreOffice 25.2.2** 📚
 
 See the [Ubuntu 25.04 Release Notes](https://discourse.ubuntu.com/t/plucky-puffin-release-notes/48687) 
@@ -49,4 +49,4 @@ The upgrade process to Ubuntu MATE 25.04 is the same as Ubuntu.
 
 There are no offline upgrade options for Ubuntu MATE. Please ensure you have
 network connectivity to one of the official mirrors or to a locally accessible
-mirror and follow the instructions above.
+mirror and follow the instructions above.