lsp: show function signature, use conform.nvim for formatting code.

config/lsp/lsp.nix

@@ -1,4 +1,4 @@
-{ helpers, ... }:
+{ pkgs, helpers, ... }:
 
 {
   plugins.lsp = {
@@ -69,6 +69,14 @@
         };
       };
     };
+    onAttach = ''
+      require("lsp_signature").on_attach({
+        bind = true,
+        handler_opts = {
+          border = "rounded"
+        };
+      }, bufnr)    
+    '';
   };
 
   keymaps = [
@@ -85,4 +93,20 @@
       };
     }
   ];
+
+  extraConfigLua = ''
+    require("lspconfig").asm_lsp.setup {
+      filetypes = { "asm", "s", "S" }
+    }
+    require("lspconfig").verible.setup { }
+  '';
+
+  extraPlugins = with pkgs.vimPlugins; [
+    lsp_signature-nvim
+  ];
+
+  extraPackages = with pkgs; [
+    asm-lsp
+    verible
+  ];
 }