Improve: Ensure shortcut directories exist in Linux installer.

Author: Sewer56

source/Reloaded.Mod.Installer.Lib/MainWindowViewModel.cs

@@ -169,11 +169,11 @@ [Desktop Entry]
 
         try
         {
-            File.WriteAllText(shortcutPath, desktopFile);
+            WriteTextWithDirectory(shortcutPath, desktopFile);
 
             // Write `.desktop` file that integrates into shell.
             var shellShortcutPath = $@"Z:/home/{userName}/.local/share/applications/{SanitizeFileName(Path.GetFileName(shortcutPath))}";
-            File.WriteAllText(shellShortcutPath, desktopFile);
+            WriteTextWithDirectory(shellShortcutPath, desktopFile);
 
             // Mark as executable.
             LinuxTryMarkAsExecutable(shortcutPath);
@@ -192,6 +192,14 @@ void ThrowFailedToCreateShortcut(Exception e)
             throw new Exception("Failed to create Reloaded shortcut.\n" +
                                 "If you have `protontricks` installed via `flatpak`, you may need to give it FileSystem permission `flatpak override --user --filesystem=host com.github.Matoking.protontricks`", e);
         }
+
+        static void WriteTextWithDirectory(string path, string content)
+        {
+            var directory = Path.GetDirectoryName(path);
+            if (!string.IsNullOrEmpty(directory))
+                Directory.CreateDirectory(directory);
+            File.WriteAllText(path, content);
+        }
     }
 
     private static void LinuxTryMarkAsExecutable(string windowsPath)