use import single classes instead of wildcard imports in Insert class.

Author: zhangkenan

src/main/java/net/sf/jsqlparser/statement/insert/Insert.java

@@ -18,7 +18,11 @@
 import net.sf.jsqlparser.statement.ReturningClause;
 import net.sf.jsqlparser.statement.Statement;
 import net.sf.jsqlparser.statement.StatementVisitor;
-import net.sf.jsqlparser.statement.select.*;
+import net.sf.jsqlparser.statement.select.PlainSelect;
+import net.sf.jsqlparser.statement.select.Select;
+import net.sf.jsqlparser.statement.select.SetOperationList;
+import net.sf.jsqlparser.statement.select.Values;
+import net.sf.jsqlparser.statement.select.WithItem;
 import net.sf.jsqlparser.statement.update.UpdateSet;
 
 import java.util.*;