Add R language support for use in ess-r-mode

[atanasj]

trafficstars

As per the heading. The repo for tree-sitter in R can be found here: https://github.com/r-lib/tree-sitter-r

[maikol-solis]

There is a package dedicated only for R tree-sitter language:

https://melpa.org/#/tree-sitter-ess-r https://github.com/ShuguangSun/tree-sitter-ess-r

I hope that tree-sitter-ess-r could be merge into the langs for maximum exposure.

Best.

[meain]

R support should now be available from https://github.com/emacs-tree-sitter/tree-sitter-langs/pull/132 and https://github.com/emacs-tree-sitter/tree-sitter-langs/pull/133