[3.11] gh-96197: Fix expression when :func:`sys.breakpointhook is missing (gh-96293)

[miss-islington]

(cherry picked from commit 47d406f)

Co-authored-by: Dong-hee Na donghee.na@python.org

• Issue: del sys.breakpointhook is not tested in test_builtin #96197

[miss-islington]

Status check is done, and it's a success ✅ .

[miss-islington]

Status check is done, and it's a success ✅ .

[miss-islington]

Status check is done, and it's a success ✅ .

[miss-islington]

Status check is done, and it's a success ✅ .

[miss-islington]

Status check is done, and it's a success ✅ .

[corona10]

lgtm bot

[marco-buttu]

I think in line 160 the reference to sys.breakpointhook should be :func:sys.breakpointhook, to be consistent with the rest of the text. Is it possible to fix also this?