fix LSPs, add c# support

fnl/plugins/init.fnl

@@ -105,13 +105,15 @@
  {repo "williamboman/mason.nvim"
   :lazy false
   :build ":MasonUpdate"
-  :opts {:ui {:border "rounded"}}}
+  :opts {:ui {:border "rounded"}
+         :registries ["github:mason-org/mason-registry"
+                      "github:Crashdummyy/mason-registry"]}}
 
  ;; Auto-install LSP servers and tools via Mason
  {repo "WhoIsSethDaniel/mason-tool-installer.nvim"
   :lazy false
   :dependencies ["williamboman/mason.nvim"]
-  :opts {:ensure_installed ["clojure-lsp" "clj-kondo" "fennel-language-server" "lua-language-server"]}}
+  :opts {:ensure_installed ["clojure-lsp" "clj-kondo" "fennel-ls" "lua-language-server" "rust-analyzer" "roslyn"]}}
 
  ;; Hop - EasyMotion-like word jumping
  {repo "smoka7/hop.nvim"
@@ -184,15 +186,23 @@
   :opts {:keymap {:preset "super-tab"
                   "<C-Space>" [(fn [cmp] (cmp.show {:providers ["supermaven"]})) :fallback]
                   "<Tab>" [:select_and_accept :snippet_forward :fallback]
-                  "<CR>" [:select_and_accept :fallback]}
-         :completion {:trigger {:show_on_keyword false
-                                :show_on_trigger_character false}
-                      :list {:selection {:preselect true :auto_insert false}}
+                  "<CR>" [:select_and_accept :fallback]
+                  "<Esc>" [:cancel :fallback]}
+         :completion {:list {:selection {:preselect true :auto_insert false}}
                       :documentation {:auto_show true}}
-         :sources {:default ["lsp" "supermaven" "path" "buffer"]
+         :sources {:default ["lsp" "path" "buffer"]
                    :providers {:supermaven {:name "Supermaven"
                                             :module "supermaven-blink"}}}}}
 
+ ;; roslyn.nvim - C# and Blazor/Razor LSP via Roslyn language server
+ ;; Must not be ft-gated: plugin/roslyn.lua calls vim.lsp.enable which needs to
+ ;; run before the FileType event fires, or existing .cs buffers won't attach.
+ {repo "seblj/roslyn.nvim"
+  :lazy false
+  :config (fn []
+            (let [roslyn (require :roslyn)]
+              (roslyn.setup {})))}
+
  ;; gitsigns.nvim - Git diff signs in the sign column
  {repo "lewis6991/gitsigns.nvim"
   :event ["BufReadPre" "BufNewFile"]