Set UTF-8 codepage in Windows manifest (#10881)

misc/minetest.exe.manifest

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
 <assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
+    <assemblyIdentity type="win32" name="minetest" version="0.0.0.0" />
     <trustInfo xmlns="urn:schemas-microsoft-com:asm.v3">
         <security>
             <requestedPrivileges>
@@ -10,6 +11,7 @@
     <application xmlns="urn:schemas-microsoft-com:asm.v3">
         <windowsSettings>
             <dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">true</dpiAware>
+            <activeCodePage xmlns="http://schemas.microsoft.com/SMI/2019/WindowsSettings">UTF-8</activeCodePage>
         </windowsSettings>
     </application>
 </assembly>