Give more information in --extendedDiagnostics

[DanielRosenwasser]

This is a list I may keep adding to as I help troubleshoot users with slow projects.

Breakdown of file types

Much of the time, users just have a lot of .d.ts files in node_modules. It'd be easier to tell the cause if I could see the breakdown of:

• .ts/.tsx files
• .d.ts files
• .js/.jsx files

I'd want to know number of lines and number of files.

Breakdown of program construction time

I've seen many examples of incorrect exclude globs that try to exclude node_modules but fail to do so.

What I'm looking for is number of folders explored during program construction time.