Move lsp config to local file structure

.config/nvim/lsp/steep.lua

@@ -0,0 +1,14 @@
+---@brief
+---
+--- https://github.com/soutaro/steep
+---
+--- `steep` is a static type checker for Ruby.
+---
+--- You need `Steepfile` to make it work. Generate it with `steep init`.
+
+---@type vim.lsp.Config
+return {
+  cmd = { 'steep', 'langserver' },
+  filetypes = { 'ruby', 'eruby' },
+  root_markers = { 'Steepfile', '.git' },
+}