fix: add some file-extension bounds to schematic loading

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

@@ -112,6 +112,15 @@ public enum BuiltInClipboardFormat implements ClipboardFormat {
             return false;
         }
 
+        @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);
+        }
+
         @Override
         public String getPrimaryFileExtension() {
             return "schem";
@@ -151,6 +160,15 @@ public enum BuiltInClipboardFormat implements ClipboardFormat {
             return detectOldSpongeSchematic(inputStream, FastSchematicWriterV2.CURRENT_VERSION);
         }
 
+        @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);
+        }
+
     },
     //FAWE end
 
@@ -177,6 +195,15 @@ public enum BuiltInClipboardFormat implements ClipboardFormat {
             //FAWE end
         }
 
+        @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);
+        }
+
         @Override
         public boolean isFormat(InputStream inputStream) {
             LinRootEntry rootEntry;