This is intended to be the start of a (not complete) coding standards
document we can refer contributors to. This can be modified to add more
nuances and become stricter over time. It can also have additional
content for other file types (CMake, YACC, etc).
It does not cover plugins which should each individually have their own coding
standards.
Many recent PRs offer up shell scripts or example queries in the testing
section, when these could be easily and usefully be converted to automated
tests based on MTR. (https://github.com/MariaDB/server/pull/1888 and
https://github.com/MariaDB/server/pull/1940 are good examples of this.)
This modifies the PR template to more strongly encourage the contribution of
automated tests.
