Revert "Add R development tools"

This reverts commit c9004ff245.

modules/software.nix

@@ -76,29 +76,27 @@
     ## Shell
     shellcheck
     shfmt
-    ## Nix
+    # Nix
     nixfmt
     niv
     ## Python
     nodePackages.pyright
     black
-    ## C/C++
+    # C/C++
     clang-tools
-    ## Javascript
+    # Javascript
     nodePackages.javascript-typescript-langserver
-    ## Go
+    # Go
     gopls
     gotests
     gore
     golangci-lint
-    ## R
-    rPackages.lintr
-    rPackages.languageserver
   ];
 
   # Fonts declaration
   fonts.fonts = with pkgs; [
     google-fonts
+    emacs-all-the-icons-fonts
     inconsolata-nerdfont
     terminus_font_ttf
     iosevka-bin