Problem/Motivation
In #2986452: Database reserved keywords need to be quoted as per the ANSI standard we fixed working with reserved keywords for queries. For the class Drupal\Core\Database\Schema there is nothing done. In #3023794: MySQL >= 8.0.2 Bug: Exception during module activation because of reserved keyword "GROUPS" we have a problem with using sites with the "group" module on Drupal 8 with MySQL 8. The problem should be fixed for Drupal 9, only for queries not for the class Drupal\Core\Database\Schema.
In #3033043: SQlite index names not quoted we have the problem: "An example of such a module is restrict_ip (https://www.drupal.org/project/restrict_ip) which defines an index named 'type-path'. The index name is perfectly valid on both MySQL and SQlite."
Proposed resolution
Add testing for working with reserved keywords in combination with the class Drupal\Core\Database\Schema. Add fixes where necessary.
Remaining tasks
TBD
User interface changes
None
API changes
None
Data model changes
None
Release notes snippet
TBD
For the committer: Please give user @jsst commit credits for his work on #3033043: SQlite index names not quoted.