Remove references to the retired Microsoft Message Analyzer in the documentation

[jdu2600]

Microsoft Message Analyzer (MMA) was retired and its download packages removed from microsoft.com sites on November 25 2019. There is currently no Microsoft replacement for Microsoft Message Analyzer in development at this time.

-- https://docs.microsoft.com/en-us/openspecs/blog/ms-winintbloglp/dd98b93c-0a75-4eb0-b92e-e760c502394f

[swannman]

This is an easy change but I'm still going through the seven stages of grief re: the retiring of Message Analyzer. 😞

I haven't found a good replacement yet. When I have one to recommend, I'll update the documentation to point to it.