Remove stray unused import

Author: oxkitsune

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/MemberOrdering.java

@@ -21,7 +21,6 @@
 import com.sun.source.tree.ClassTree;
 import com.sun.source.tree.MethodTree;
 import com.sun.source.tree.Tree;
-import com.sun.source.tree.Tree.Kind;
 import com.sun.source.tree.VariableTree;
 import com.sun.source.util.TreePath;
 import com.sun.tools.javac.parser.Tokens;