chore(docs): add docs

lua/gopher/config.lua

@@ -69,12 +69,24 @@ local default_config = {
     ---@type string|nil
     option = nil,
   },
+  ---@class gopher.ConfigIfErr
   iferr = {
     -- choose a custom error message, nil to use default
     -- e.g: `message = 'fmt.Errorf("failed to %w", err)'`
     ---@type string|nil
     message = nil,
   },
+  ---@class gopher.ConfigJson2Go
+  json2go = {
+    -- command used to open interactive input.
+    -- e.g: `split`, `botright split`, `tabnew`
+    interactive_cmd = "vsplit",
+
+    -- name of autogenerated struct, if nil none, will the default one of json2go.
+    -- e.g: "MySuperCoolName"
+    ---@type string|nil
+    type_name = nil,
+  },
 }
 --minidoc_afterlines_end
 
@@ -105,6 +117,7 @@ function config.setup(user_config)
   vim.validate("commands.gotests", _config.commands.gotests, "string")
   vim.validate("commands.impl", _config.commands.impl, "string")
   vim.validate("commands.iferr", _config.commands.iferr, "string")
+  vim.validate("commands.json2go", _config.commands.json2go, "string")
   vim.validate("gotests", _config.gotests, "table")
   vim.validate("gotests.template", _config.gotests.template, "string")
   vim.validate("gotests.template_dir", _config.gotests.template_dir, { "string", "nil" })
@@ -115,6 +128,8 @@ function config.setup(user_config)
   vim.validate("gotag.option", _config.gotag.option, { "string", "nil" })
   vim.validate("iferr", _config.iferr, "table")
   vim.validate("iferr.message", _config.iferr.message, { "string", "nil" })
+  vim.validate("json2go.installer_timeout", _config.json2go.interactive_cmd, "string")
+  vim.validate("json2go.type_name", _config.json2go.type_name, { "string", "nil" })
 end
 
 setmetatable(config, {