Clarify --diagnostics report units

I've been recently looking at parsing --diagnostics output to report to out metrics service so that we can monitor compile times and while attempting to normalize values to a common unit (e.g. durations to seconds and memory used to MB), I've noticed that the docs are not very clear about the metric definitions and their respective units.

I would love if the docs specified what are the possible units that may be reported for each metric. For instance, can Total time be reported in milliseconds or even minutes right now? I see that memory used is reported as K, I assume that is kilobytes, but I'm not sure.

Less importantly, but in a similar vein, the duration timings (parse, bind, check, emit and total time) do not specify if these metrics are reported in wall time or CPU time. (it doesnt make much difference for our purposes, but it would be good to know how the metric may be affected).

If someone can point me to the relevant files where these metrics are measured, I would happy to take a stab at opening a PR :)

Thanks so much!

Start at the TypeScript compiler's --diagnostics output and locate the documentation and metric definitions for parse, bind, check, emit, total time, and memory used. Clarify each metric's possible units and whether timings use wall time or CPU time; done means the documentation answers these questions for someone parsing the report.