docs: add note for FrecencyOpts (#208)

* docs: add lacked help tags

* docs: add FrecencyOpts and its explanation

doc/telescope-frecency.txt

@@ -166,6 +166,7 @@ or to map to a key:
 Filter tags are applied by typing the `:tag:` name (adding surrounding colons)
 in the finder query. Entering `:<Tab>` will trigger omni completion |compl-omni|.
 
+		       *telescope-frecency-usage-dealing-with-uppercase-letters*
 ------------------------------------------------------------------------------
 Dealing with upper case letters
 
@@ -228,6 +229,24 @@ You can call `setup()` with these configuration settings below.
 	},
       },
     }
+<
+				 *telescope-frecency-configuration-frecencyopts*
+								  *FrecencyOpts*
+`FrecencyOpts` is a convenient type to use your own configuration. With using
+this in the type annotation, you can complete items by LSP in writing.
+
+NOTE: You need a properly configured Language Server for this feature such as
+lua-ls. https://github.com/LuaLS/lua-language-server
+>lua
+    require("telescope").setup {
+      extensions = {
+	---@type FrecencyOpts
+	frecency = {
+	  auto_validate = false,
+	  -- …… other configs
+	}
+      },
+    }
 <
 			        *telescope-frecency-configuration-auto_validate*
 auto_validate ~

lua/frecency/config.lua

@@ -1,5 +1,27 @@
 local os_util = require "frecency.os_util"
 
+---Type to use when users write their own config.
+---@class FrecencyOpts
+---@field recency_values? { age: integer, value: integer }[] default: see lua/frecency/config.lua
+---@field auto_validate? boolean default: true
+---@field db_root? string default: vim.fn.stdpath "state"
+---@field db_safe_mode? boolean default: true
+---@field db_validate_threshold? integer default: 10
+---@field default_workspace? string default: nil
+---@field disable_devicons? boolean default: false
+---@field filter_delimiter? string default: ":"
+---@field hide_current_buffer? boolean default: false
+---@field ignore_patterns? string[] default: { "*.git/*", "*/tmp/*", "term://*" }
+---@field matcher? "default"|"fuzzy" default: "default"
+---@field scoring_function? fun(recency: integer, fzy_score: number): number default: see lua/frecency/config.lua
+---@field max_timestamps? integer default: 10
+---@field path_display? table default: nil
+---@field show_filter_column? boolean|string[] default: true
+---@field show_scores? boolean default: false
+---@field show_unindexed? boolean default: true
+---@field workspace_scan_cmd? "LUA"|string[] default: nil
+---@field workspaces? table<string, string> default: {}
+
 ---@class FrecencyConfig: FrecencyRawConfig
 ---@field ext_config FrecencyRawConfig
 ---@field private values FrecencyRawConfig