[CPyCppyy] Fix regression in passing buffers through void *

[guitargeek]

Credit goes to Wim Lavrijsen (@wlav).

See also: wlav/cppyy#272.

Following up on #16816, hopefully fixing the problem without sacrificing any features.

[github-actions]

Test Results

    18 files      18 suites   3d 19h 12m 18s ⏱️
 2 664 tests  2 664 ✅ 0 💤 0 ❌
46 152 runs  46 152 ✅ 0 💤 0 ❌

Results for commit 8687a02.

[vepadulano]

Just a minor curiosity, rest looks good thanks!

[vepadulano]

I'm just curious to understand why the extra title kwarg, which looks like it's unused in the function

[guitargeek]

That's more of a question to @wlav who wrote this. But for ROOT it makes no difference at this point.

But let's try to run all these tests also in our CI in the future!

[wlav]

The interface of the pydoc pager changed in 3.13 with the addition of that title argument, but I'd rather have the test capture the same information only, i.e. the help-text body, than introduce differences in test behavior between versions. (If anything needs changing, this test needs a teardown to restore the old pager.)