RkeOps broken since v2.3

[bcharlier]

Everything is in the title

• Current rkeops should pin the pykeops version to 2.2.3
• On a Ubuntu 24.04, reticulate complain: an incompatible NumPy binary version 33554432 (expecting version 16777225) (agressive upgrade in venv creation...) work if i pin numpy to 1.26.4
• many typo in doc (M, N switch, use_cpu() / use_gpu() -> rkeops_use_cpu(), etc...)

[joanglaunes]

A quick temporary fix could be to pin pykeops version to 2.2.3 :

keops/rkeops/R/install.R

Line 56 in 0152630

packages = "pykeops",

[gdurif]

Works in progress on branch https://github.com/getkeops/keops/tree/fix_rkeops_v2_keops_v2.3

PR incoming

[gdurif]

Fixed by #428