Use covariant return types in non-generated clone methods

src/main/java/org/sablecc/sablecc/CharSet.java

@@ -34,7 +34,7 @@ public class CharSet implements Cloneable
   }
 
   @Override
-  public Object clone()
+  public CharSet clone()
   {
     return new CharSet(intervals);
   }
@@ -183,7 +183,7 @@ public class CharSet implements Cloneable
     }
 
     @Override
-    public Object clone()
+    public Interval clone()
     {
       return new Interval(start, end);
     }

src/main/java/org/sablecc/sablecc/IntSet.java

@@ -82,7 +82,7 @@ public class IntSet
   }
 
   @Override
-  public Object clone()
+  public IntSet clone()
   {
     return new IntSet(this);
   }

src/main/java/org/sablecc/sablecc/LR0Item.java

@@ -36,7 +36,7 @@ final class LR0Item implements Cloneable, Comparable
   }
 
   @Override
-  public Object clone()
+  public LR0Item clone()
   {
     return new LR0Item(production, position);
   }

src/main/java/org/sablecc/sablecc/LR0ItemSet.java

@@ -108,7 +108,7 @@ final class LR0ItemSet implements Cloneable, Comparable
   }
 
   @Override
-  public Object clone()
+  public LR0ItemSet clone()
   {
     return new LR0ItemSet(this);
   }

src/main/java/org/sablecc/sablecc/LR1Item.java

@@ -21,7 +21,7 @@ final class LR1Item implements Cloneable, Comparable
   }
 
   @Override
-  public Object clone()
+  public LR1Item clone()
   {
     return new LR1Item(lr0Item, terminal);
   }

src/main/java/org/sablecc/sablecc/LR1ItemSet.java

@@ -162,7 +162,7 @@ final class LR1ItemSet implements Cloneable, Comparable
   }
 
   @Override
-  public Object clone()
+  public LR1ItemSet clone()
   {
     return new LR1ItemSet(this);
   }

src/main/java/org/sablecc/sablecc/NFA.java

@@ -270,7 +270,7 @@ public class NFA implements Cloneable
   }
 
   @Override
-  public Object clone()
+  public NFA clone()
   {
     return new NFA(this);
   }

src/main/java/org/sablecc/sablecc/SymbolSet.java

@@ -204,7 +204,7 @@ final class SymbolSet implements Cloneable
   }
 
   @Override
-  public Object clone()
+  public SymbolSet clone()
   {
     return new SymbolSet(this);
   }