[Chapel Merge] Update the GPU technote

Branch: refs/heads/main
Revision: 5ae1d22
Author: e-kayrakli
Link: Unavailable
Log Message:

Merge pull request #19470 from e-kayrakli/gpu-doc

Update the GPU technote

Besides some cosmetic changes this PR:

  • Makes the title simply "GPU Programming",
  • Drops K20, adds A100 as the tested system,
  • Drops single-gpu limitation.

[OK'ed by the GPU team]