Add nil and zls LSP's

nvim/lua/lsp/servers/nil.lua

@@ -0,0 +1,15 @@
+return {
+    cmd = { "nil" },
+    filetypes = { "nix" },
+    root_markers = {
+        "flake.nix",
+        ".git"
+    },
+    settings = {
+        ["nil"] = {
+            formatting = {
+                command = { "nixfmt" },
+            },
+        },
+    },
+}

nvim/lua/lsp/servers/zls.lua

@@ -0,0 +1,10 @@
+return {
+    cmd = { "zls" },
+    on_new_config = function(new_config, new_root_dir)
+      if vim.fn.filereadable(vim.fs.joinpath(new_root_dir, "zls.json")) ~= 0 then
+        new_config.cmd = { "zls", "--config-path", "zls.json" }
+      end
+    end,
+    filetypes = { "zig", "zir" },
+    root_markers = {"zls.json", "build.zig", ".git"},
+}