PARTITION BY RANGE vs PARTITION BY RANGE COLUMNS are not clear

Change Request

Please answer the following questions before submitting your issue. Thanks!

1. Describe what you find is inappropriate or missing in the existing docs.

I cannot see what the difference between PARTITION BY RANGE (col) and PARTITION BY RANGE COLUMNS (col).

2. Describe your suggestion or addition.

The difference is that RANGE COLUMNS(col) can take most types of columns, while RANGE (col) only take int columns.
See:

tidb> create table t (a int, b varchar(255)) partition by range (b) (partition p1 values less than (""));
ERROR 1697 (HY000): VALUES value for partition 'p1' must have type INT
tidb> create table t (a int, b varchar(255)) partition by range (b) (partition p1 values less than (1));
ERROR 1659 (HY000): Field 'b' is of a not allowed type for this type of partitioning
tidb> create table t (a int, b varchar(255)) partition by range columns (b) (partition p1 values less than (""));
Query OK, 0 rows affected (0,00 sec)

3. Provide some reference materials (documents, websites, etc) if you could.

https://dev.mysql.com/doc/refman/8.0/en/partitioning-types.html
https://dev.mysql.com/doc/refman/8.0/en/partitioning-columns.html

Start by reading the existing TiDB partitioning documentation and compare it with the cited MySQL pages on partitioning types and partitioning columns. Clarify the distinction between RANGE and RANGE COLUMNS, including the supported column types and representative examples; the documentation is done when readers can choose the appropriate syntax from the page alone.