[3.10] [3.11] Add single value `agen.athrow(value)` signature to the 3.11 docs gh-105269 (GH-105468) (#105480)

(cherry picked from commit acf3916e84158308660ed07c474a564e045d6884)

Co-authored-by: Federico Caselli <CaselIT@users.noreply.github.com>