Rollup merge of #140220 - GuillaumeGomez:doctest-main-wrapping, r=fmease

Fix detection of main function if there are expressions around it

Fixes #140162.
Fixes #139651.

Once this is merged, we can backport and I'll send a follow-up to emit a warning in case a `main` function is about to be "wrapped" (and therefore not run).

r? `@fmease`

try-job: x86_64-mingw-1

Author: GuillaumeGomez