[math] implement genvector custom axis rotation

[ferdymercury]

This Pull request:

Changes or fixes:

Fixes https://root-forum.cern.ch/t/tvector3-rotate-to-arbitrary-rotation-using-xyzvector/63244

Checklist:

• tested changes locally
• updated the docs (if necessary)

[github-actions]

Test Results

    19 files      19 suites   4d 10h 23m 26s ⏱️
 2 731 tests  2 731 ✅ 0 💤 0 ❌
50 450 runs  50 450 ✅ 0 💤 0 ❌

Results for commit 96fb2e8.

♻️ This comment has been updated with latest results.

[chrishanw]

Thanks for this PR. As I wrote in the forum post, the new Rotate function solves the issue for rotating a XYZVector around an arbitrary axis.

Edit: Of course the other solution implemented in #18480 will also solve the issue by enabling the usage of Rotation3D, Thanks!

[hageboeck]

Hello @ferdymercury,

thanks for taking this up! Also here, having a small test would make it easier to judge what's going on.

One more function in https://github.com/root-project/root/blob/master/math/genvector/test/stress3D.cxx maybe.
Better here: https://github.com/root-project/root/blob/master/math/genvector/test/testGenVector.cxx

Added, thanks!

[hageboeck]

Thanks @ferdymercury! LGTM!
Let's wait for the builds to complete.