Document Run's @TestResultFormatter parameter

[nsturmwind]

https://tsqlt.org/user-guide/test-creation-and-execution/run/ does not mention the @TestResultFormatter parameter.

It looks like the valid values for @TestResultFormatter are tSQLt.DefaultResultFormatter, tSQLt.NullTestResultFormatter, and tSQLt.XmlResultFormatter.

[mbt1]

We are looking for volunteers to move the docs to GitHub, so that enhancements to the documentation like this can be submitted via PR. Are you interested in helping us with this task, @nsturmwind?