string-functions: Use MySQL 8.0 url instead of 8.3 (#18243)

functions-and-operators/string-functions.md

@@ -541,7 +541,7 @@ Arguments:
 
 - `X`: the number to be formatted. It can be a direct numeric value, a numeric string, or a number in scientific notation.
 - `D`: the number of decimal places for the returned value. The function rounds the number `X` to `D` decimal places. If `D` is greater than the actual number of decimal places in `X`, the result is padded with zeros to the corresponding length.
-- `[locale]`: specifies a locale setting to be used for grouping between decimal points, thousands separators, and separators for resultant numbers. A valid locale value is the same as the valid value of the [`lc_time_names`](https://dev.mysql.com/doc/refman/8.3/en/server-system-variables.html#sysvar_lc_time_names) system variable. If not specified or the region setting is `NULL`, the `'en_US'` region setting is used by default. This argument is optional.
+- `[locale]`: specifies a locale setting to be used for grouping between decimal points, thousands separators, and separators for resultant numbers. A valid locale value is the same as the valid value of the [`lc_time_names`](https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_lc_time_names) system variable. If not specified or the region setting is `NULL`, the `'en_US'` region setting is used by default. This argument is optional.
 
 Behaviors:
 
@@ -2373,4 +2373,4 @@ The difference between TiDB and MySQL support for the binary string type:
 
 ### Known issues
 
-- [GitHub Issue #37981](https://github.com/pingcap/tidb/issues/37981)
+- [GitHub Issue #37981](https://github.com/pingcap/tidb/issues/37981)