fixed tsqlite_statement bugs

include/tsqlite.h

@@ -53,8 +53,19 @@ Result(tsqlite_statement*) tsqlite_statement_compile(tsqlite_connection* conn, s
 
 void tsqlite_statement_free(tsqlite_statement* st);
 
-/// @brief execute statement or move to next result row. Documentation: https://sqlite.org/c3ref/step.html
-/// @return is next result row avaliable
+/// @brief execute statement or move to next result row.
+/// Documentation: https://sqlite.org/c3ref/step.html
+/// 
+/// USAGE: 
+/// ```
+/// while(true){
+///     try(bool has_result, i, tsqlite_statement_execNext(st));
+///     if(!has_result)
+///         break;
+///     /* get result columns */
+/// }
+/// ```
+/// @return is result row avaliable
 Result(bool) tsqlite_statement_execNext(tsqlite_statement* self);
 
 /// call this after executing a compiled statement to use it again