Change sln solution file to slnx (#774)

Author: gamebit8

src/routes/docs/contributing/building-from-source/+page.md

@@ -4,7 +4,7 @@ title: Compiling the source code
 
 ### 1: Prerequisites
 
-- [Visual Studio 2022](https://visualstudio.microsoft.com/vs/) with the following individual components:
+- [Visual Studio 2022 17.13 or later](https://visualstudio.microsoft.com/vs/) with the following individual components:
   - Windows 11 SDK (10.0.22621.0)
   - .NET 9 SDK (version 9.0.200)
   - MSVC v143 - VS 2022 C++ x64/x86 or ARM64 build tools (latest)
@@ -22,7 +22,7 @@ This will create a local copy of the repository.
 
 ### 3: Deploy the project in Visual Studio
 
-To build the app in development mode, open the sln file in Visual Studio (Files.sln) and set the Files.Package project as the startup item by right-clicking on `Files.Package` in the solution explorer & hitting ‘Set as Startup item’.
+To build the app in development mode, open the slnx file in Visual Studio (Files.slnx) and set the Files.Package project as the startup item by right-clicking on `Files.Package` in the solution explorer & hitting ‘Set as Startup item’.
 
 In the architecture pane, select the correct architecture for your system as `Debug` which should look like this: