Update signal hander user info more compassion and correct url

The blame shifting in the error " It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware." is a little rare to mention.

https://mariadb.com/kb/en/how-to-produce-a-full-stack-trace-for-mariadbd/ is the url now too instead of ...for-mysqld