System Databases section of manual is confusing

[wwar]

Change Request

This repository is ONLY used to solve issues related to DOCS.
For other issues (related to TiDB, PD, etc), please move to other repositories.

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

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

See: https://pingcap.com/docs/stable/system-tables/system-table-cluster-info/

The structure has the following as system databases (as formatted code):

mysql
information_schema
sql-diagnosis

But if I use mysql, the system databases are:

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| INFORMATION_SCHEMA |
| METRICS_SCHEMA     |
| PERFORMANCE_SCHEMA |
| mysql              |
| test               |
+--------------------+
5 rows in set (0.00 sec)

2. Describe your suggestion or addition.

These show really correspond to where they are in the product. For example, some of the ones under sql-diagnosis are actually information_schema tables.

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

[toutdesuite]

@crazycs520 PTAL, thanks~

I would like to work on this if that works for you?