[clang] [analyzer] Set and display CSA analysis entry points as notes on debugging (PR #84823)

[Balazs Benics via cfe-commits]

steakhal wrote:

> However, I feel an urge to bikeshed that the "[invisible]" prefix is a bit puzzling for the developer who encounters it. Consider replacing it with the prefix "[debug]" which is a more conventional signal for "this is a debug printout" (i.e. normal users won't see it). Another alternative could be adding the name of the command-line flag either before or after the printout to explain and highlight its origin (similarly to the way how the checker name is printed).

I'm fine with either of those.
Did you envision `[debug] XYZ`, and `XYZ [-analyzer-note-analysis-entry-points]`?
Which should I pursue?

> By the way what's the reason for implementing this as a command-line flag instead of a checker in the `debug` group? (I'd presume that a debug checker would involve more boilerplate.)

I don't see currently a way to hook all `emitReport` calls from a different checker.
Note that this flag alters most CSA diagnostics, like path-sensitive ones,and also some non-path-sensitive ones, such as the one that the DeadStores checker emits.

https://github.com/llvm/llvm-project/pull/84823