[llvm] [docs][TypeProf]Update instrumentation file format document (PR #83309)

[Mingming Liu via llvm-commits]

minglotus-6 wrote:

thanks for the review! On a second look I found this PR doesn't update ASCII art and header for indexed profiles.

I will send out a separate PR to make indexed profile ASCII art and header more general and high-level -> pointing users to look at source code to know the exact fields, and document the high-level summary that offsets are used to indicate the position of sections.

https://github.com/llvm/llvm-project/pull/83309