feat(select): allow user to override format_item (#6)

doc/dressing.txt

@@ -130,5 +130,23 @@ pass `prompt_buffer = true` to use that implementation.
 There are slight visual differences in where the "prompt" text in placed, but
 otherwise they should be functionally identical.
 
+===============================================================================
+                                                                *dressing-format*
+Sometimes you may wish to change how choices are displayed for
+`vim.ui.select`. The calling function can pass a specific "kind" to the select
+function (for example, code actions from |vim.lsp.buf.code_action|
+use kind="codeaction"). You can, in turn, specify an override for the
+"format_item" function when selecting for that kind. For example, this
+configuration will display the name of the language server next to code
+actions:
+>
+    format_item_override = {
+      codeaction = function(action_tuple)
+        local title = action_tuple[2].title:gsub("\r\n", "\\r\\n")
+        local client = vim.lsp.get_client_by_id(action_tuple[1])
+        return string.format("%s\t[%s]", title:gsub("\n", "\\n"), client.name)
+      end,
+    }
+
 ===============================================================================
 vim:ft=help:et:ts=2:sw=2:sts=2:norl

doc/tags

@@ -1,6 +1,7 @@
 Dressing	dressing.txt	/*Dressing*
 dressing	dressing.txt	/*dressing*
 dressing-configuration	dressing.txt	/*dressing-configuration*
+dressing-format	dressing.txt	/*dressing-format*
 dressing-prompt	dressing.txt	/*dressing-prompt*
 dressing.nvim	dressing.txt	/*dressing.nvim*
 dressing.txt	dressing.txt	/*dressing.txt*

lua/dressing/config.lua

@@ -78,6 +78,9 @@ local default_config = {
       min_height = 10,
     },
 
+    -- Used to override format_item. See :help dressing-format
+    format_item_override = {},
+
     -- see :help dressing_get_config
     get_config = nil,
   },

lua/dressing/select/init.lua

@@ -28,8 +28,11 @@ return function(items, opts, on_choice)
   opts = opts or {}
   local config = global_config.get_mod_config("select", opts)
   opts.prompt = opts.prompt or "Select one of:"
-  if opts.format_item then
-    -- Make format_item doesn't *technically* have to return a string for the
+  local format_override = config.format_item_override[opts.kind]
+  if format_override then
+    opts.format_item = format_override
+  elseif opts.format_item then
+    -- format_item doesn't *technically* have to return a string for the
     -- core implementation. We should maintain compatibility by wrapping the
     -- return value with tostring
     local format_item = opts.format_item