fix csharp

ftplugin/cs.lua

@@ -1 +1 @@
-require("lsp").setup "csharp"
+require("lsp").setup "cs"

lua/default-config.lua

@@ -117,11 +117,12 @@ lvim.lang = {
       },
     },
   },
-  csharp = {
+  cs = {
     formatter = {
       exe = "",
       args = {},
     },
+    linters = {},
     lsp = {
       provider = "omnisharp",
       setup = {

lua/lsp/null-ls.lua

@@ -62,10 +62,12 @@ local function setup(filetype, type)
 
   if is_table(executables) then
     for _, exe in pairs(executables) do
-      setup_ls(exe, type)
+      if exe ~= "" then
+        setup_ls(exe, type)
+      end
     end
   end
-  if is_string(executables) then
+  if is_string(executables) and executables ~= "" then
     setup_ls(executables, type)
   end
 end