mysql: Change mtop to mytop

[MaxValue]

There seems to be a typo in this manual:

At this heading there is the mention of a tool called mtop which does not exist. I guess it was meant to say mytop?

Relevant file: /source/database-mysql.rst

[noave]

there is a tool named mtop that can be used in the way like described in the manual, but with the updated mariadb came also mytop which seems to be better suited for using (no additional configuration needed), we already had the idea of replacing it in the manual. keeping this as a issues open for that suggestion :-)

[noave]

mytop is now already documented and replaced mtop