RFC: Clarify numeric values as they relate to webpack compilation

[cdaringe]

Is your feature request related to a problem? Please describe.

When studying a report from statoscope, sometimes I am unclear if the module under study:

• is reporting size values after is has been tree shaken
• is reporting size values after is has been thru my terser/minification
• if size values associated with modules are from the source, or from the webpack processed instance of the module
  • example: if module X is export const foo = "bar" and export const bar = "baz", but my front end compilation tree shaked foo out of the module, does the reported size compensate for this, or is the output just a simple analysis for the original source module? if a final value is available, can we report it, or view it instead of the full source module?

Describe the solution you'd like

• clarify, in documentation, how to interpret values

Describe alternatives you've considered

• annotate via tooltips the meaning of values in the UI

Additional context

none

[cdaringe]

What i'm after is specifically:

https://github.com/webpack-contrib/webpack-bundle-analyzer/tree/e5b617e44df299e7ad4f7dc1bb1cac41e204648c#size-definitions

It looks like it's showing stat | gzip, but it would be awesome to show parsed!