Continue the effort of a previous commit (PR#2114) which changed the man
pages titles from MariaDB to MySQL, to further update the man pages.

Update the man page NAME sections to use mariadb-* instead of mysql* for
MariaDB binaries that are drop-in replacements for MySQL equivalents,
indicating that the commands are actually of the MariaDB version.

Before:
    NAME
        mysql_upgrade - check tables for MariaDB upgrade
    ...

After:
    NAME
        mariadb-upgrade - check tables for MariaDB upgrade (mysql_upgrade
        is now a symlink to mariadb-upgrade)
    ...

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services, Inc.