Move Nix files into a nix directory

Move everything from `config` to the root level.

nvim/lua/opdavies/lsp/handlers.lua

@@ -0,0 +1,73 @@
+local M = {}
+
+local function should_remove_diagnostic(messages_to_filter, message)
+  for _, filter_message in ipairs(messages_to_filter) do
+    if message:match(filter_message) then
+      return true
+    end
+  end
+
+  return false
+end
+
+M.definition = function()
+  local params = vim.lsp.util.make_position_params()
+
+  vim.lsp.buf_request(0, "textDocument/definition", params, function(err, result, ctx, config)
+    local bufnr = ctx.bufnr
+    local ft = vim.api.nvim_buf_get_option(bufnr, "filetype")
+
+    local new_result = vim.tbl_filter(function(v)
+      -- Remove any definitions within the nix store via the .direnv directory.
+      if string.find(v.targetUri, ".direnv") then
+        return false
+      end
+
+      -- Remove definitions within vendor-bin directory for PHP files.
+      if ft == "php" then
+        if string.find(v.targetUri, "vendor%-bin") then
+          return false
+        end
+      end
+
+      return true
+    end, result)
+
+    if #new_result > 0 then
+      result = new_result
+    end
+
+    vim.lsp.handlers["textDocument/definition"](err, result, ctx, config)
+    vim.cmd [[normal! zz]]
+  end)
+end
+
+M.on_publish_diagnostics = function(_, result, ctx, config)
+  local client = vim.lsp.get_client_by_id(ctx.client_id)
+
+  if client.name == "cssls" then
+    local filtered_diagnostics = {}
+
+    local messages_to_filter = {
+      "Unknown at rule @apply",
+      "Unknown at rule @plugin",
+      "Unknown at rule @tailwind",
+      "Unknown at rule @theme",
+    }
+
+    -- For each diagnostic, ensure its mesages doesn't match one I want to
+    -- ignore before adding it to the result. If it matches, don't add it to the
+    -- result and it won't be shown.
+    for _, diagnostic in ipairs(result.diagnostics) do
+      if not should_remove_diagnostic(messages_to_filter, diagnostic.message) then
+        table.insert(filtered_diagnostics, diagnostic)
+      end
+    end
+
+    result.diagnostics = filtered_diagnostics
+  end
+
+  vim.lsp.diagnostic.on_publish_diagnostics(_, result, ctx, config)
+end
+
+return M