Move lsp config to local file structure

.config/nvim/lsp/gh_actions_ls.lua

@@ -0,0 +1,57 @@
+---@brief
+--- https://github.com/lttb/gh-actions-language-server
+---
+--- Language server for GitHub Actions.
+---
+--- The projects [forgejo](https://forgejo.org/) and [gitea](https://about.gitea.com/)
+--- design their actions to be as compatible to github as possible
+--- with only [a few differences](https://docs.gitea.com/usage/actions/comparison#unsupported-workflows-syntax) between the systems.
+--- The `gh_actions_ls` is therefore enabled for those `yaml` files as well.
+---
+--- The `gh-actions-language-server` can be installed via `npm`:
+---
+--- ```sh
+--- npm install -g gh-actions-language-server
+--- ```
+
+---@type vim.lsp.Config
+return {
+  cmd = { 'gh-actions-language-server', '--stdio' },
+  filetypes = { 'yaml' },
+
+  -- `root_dir` ensures that the LSP does not attach to all yaml files
+  root_dir = function(bufnr, on_dir)
+    local parent = vim.fs.dirname(vim.api.nvim_buf_get_name(bufnr))
+    if
+      vim.endswith(parent, '/.github/workflows')
+      or vim.endswith(parent, '/.forgejo/workflows')
+      or vim.endswith(parent, '/.gitea/workflows')
+    then
+      on_dir(parent)
+    end
+  end,
+  handlers = {
+    ['actions/readFile'] = function(_, result)
+      if type(result.path) ~= 'string' then
+        return nil, nil
+      end
+      local file_path = vim.uri_to_fname(result.path)
+      if vim.fn.filereadable(file_path) == 1 then
+        local f = assert(io.open(file_path, 'r'))
+        local text = f:read('*a')
+        f:close()
+
+        return text, nil
+      end
+      return nil, nil
+    end,
+  },
+  init_options = {}, -- needs to be present https://github.com/neovim/nvim-lspconfig/pull/3713#issuecomment-2857394868
+  capabilities = {
+    workspace = {
+      didChangeWorkspaceFolders = {
+        dynamicRegistration = true,
+      },
+    },
+  },
+}