feat(r): add R languageserver for Neovim LSP

- Add languageserver to settings.lang_packages.r
- Enable r_language_server in LSP config (plugin/25_lsp.lua)

flake.nix

@@ -59,6 +59,7 @@
             broom
             data_table
             janitor
+            languageserver
             styler
           ];
           julia = ["DataFramesMeta" "QuackIO"];

plugin/25_lsp.lua

@@ -15,17 +15,17 @@ now_if_args(function()
     marksman = {
       filetypes = { "markdown", "markdown_inline", "codecompanion" },
     },
-    -- r_language_server = {
-    --   filetypes = { 'r', 'rmd', 'rmarkdown' },
-    --   settings = {
-    --     ['r_language_server'] = {
-    --       lsp = {
-    --         rich_documentation = true,
-    --         enable = true,
-    --       },
-    --     },
-    --   }
-    -- },
+    r_language_server = {
+      filetypes = { 'r', 'rmd', 'rmarkdown' },
+      settings = {
+        ['r_language_server'] = {
+          lsp = {
+            rich_documentation = true,
+            enable = true,
+          },
+        },
+      }
+    },
     julials = {
       settings = {
         julia = {