Make Plugin class sealed and update file extension list

Marked the Plugin class as sealed to prevent inheritance. Commented out several file extensions in the WellKnownExtensions set, likely to restrict the plugin to more common certificate file types.

Author: emako

QuickLook.Plugin/QuickLook.Plugin.CertViewer/Plugin.cs

@@ -6,7 +6,7 @@
 
 namespace QuickLook.Plugin.CertViewer;
 
-public class Plugin : IViewer
+public sealed class Plugin : IViewer
 {
     private static readonly HashSet<string> WellKnownExtensions = new(StringComparer.OrdinalIgnoreCase)
     {
@@ -15,13 +15,13 @@ public class Plugin : IViewer
         ".cer", // Certificate file (DER or PEM encoded, usually contains only the public certificate)
         ".crt", // Certificate file (similar to .cer, common on UNIX/Linux)
         ".pem", // PEM encoded certificate or key file (can contain certificate, private key, or CA chain)
-        ".snk", // Strong Name Key file (.NET strong name key pair)
-        ".pvk", // Private key file (usually used with .spc)
-        ".spc", // Software Publisher Certificate
+        //".snk", // Strong Name Key file (.NET strong name key pair)
+        //".pvk", // Private key file (usually used with .spc)
+        //".spc", // Software Publisher Certificate
         ".mobileprovision", // Apple mobile device provisioning profile (contains certificates, public keys, etc.)
         ".certSigningRequest", // Certificate Signing Request (usually .csr)
-        ".csr", // Certificate Signing Request
-        ".keystore", // Java keystore file (usually stores certificates and private keys)
+        //".csr", // Certificate Signing Request
+        //".keystore", // Java keystore file (usually stores certificates and private keys)
     };
 
     private CertViewerControl _control;