fix: schematic format detection

Author: PierreSchwang

worldedit-core/src/main/java/com/sk89q/worldedit/extent/clipboard/io/BuiltInClipboardFormat.java

@@ -52,6 +52,8 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.nio.file.Files;
+import java.nio.file.StandardOpenOption;
 import java.util.Collections;
 import java.util.Locale;
 import java.util.Set;
@@ -118,10 +120,7 @@ public boolean isFormat(final InputStream inputStream) {
         @Override
         public boolean isFormat(File file) {
             String name = file.getName().toLowerCase(Locale.ROOT);
-            if (name.endsWith(".schematic") || name.endsWith(".mcedit") || name.endsWith(".mce")) {
-                return false;
-            }
-            return super.isFormat(file);
+            return name.endsWith(".schem") && super.isFormat(file);
         }
 
         @Override
@@ -261,7 +260,11 @@ public boolean isFormat(InputStream inputStream) {
 
         @Override
         public boolean isFormat(File file) {
-            return MCEDIT_SCHEMATIC.isFormat(file);
+            final String filename = file.getName().toLowerCase(Locale.ROOT);
+            if (!filename.endsWith(".schematic") && !filename.endsWith(".schem")) {
+                return false;
+            }
+            return super.isFormat(file);
         }
 
         @Override
@@ -272,7 +275,7 @@ public Set<String> getExplicitFileExtensions() {
 
     /**
      * @deprecated Slow, resource intensive, but sometimes safer than using the recommended
-     *         {@link BuiltInClipboardFormat#FAST}.
+     *         {@link BuiltInClipboardFormat#FAST_V2}.
      *         Avoid using with any large schematics/clipboards for reading/writing.
      */
     @Deprecated