feat(struct_tags): set default tag (#87)

* feat(struct_tags): add config option for default tag

* docs: docgen

* fix(struct_tags): as it turns out it didnt work as i supposed to before, but now it does

doc/gopher.nvim.txt

···
     ---@type number
     log_level = vim.log.levels.INFO,
 
+    -- timeout for running commands
+    ---@type number
+    timeout = 2000,
+
     -- user specified paths to binaries
     ---@class gopher.ConfigCommand
     commands = {
···
     gotag = {
       ---@type gopher.ConfigGoTagTransform
       transform = "snakecase",
+
+      -- default tags to add to struct fields
+      default_tag = "json",
     },
   }
 <

lua/gopher/config.lua

···
   gotag = {
     ---@type gopher.ConfigGoTagTransform
     transform = "snakecase",
+
+    -- default tags to add to struct fields
+    default_tag = "json",
   },
 }
 --minidoc_afterlines_end

lua/gopher/struct_tags.lua

···
     table.insert(cmd_args, v)
   end
 
-  -- set default tag for "clear tags"
-  if #arg == 1 and arg[1] ~= "-clear-tags" then
-    table.insert(cmd_args, "json")
-  end
-
   local rs = r.sync {
     c.commands.gomodifytags,
     "-transform",
···
 
 -- add tags to struct under cursor
 function struct_tags.add(...)
-  local arg = { ... }
-  if #arg == nil or arg == "" then
-    arg = { "json" }
+  local user_tags = { ... }
+  if #user_tags == 0 then
+    vim.print("c.gotag.default_tag", c.gotag.default_tag)
+    user_tags = { c.gotag.default_tag }
   end
 
   local cmd_args = { "-add-tags" }
-  for _, v in ipairs(arg) do
+  for _, v in ipairs(user_tags) do
     table.insert(cmd_args, v)
   end
 
···
 
 -- remove tags to struct under cursor
 function struct_tags.remove(...)
-  local arg = { ... }
-  if #arg == nil or arg == "" then
-    arg = { "json" }
+  local user_tags = { ... }
+  if #user_tags == 0 then
+    user_tags = { c.gotag.default_tag }
   end
 
   local cmd_args = { "-remove-tags" }
-  for _, v in ipairs(arg) do
+  for _, v in ipairs(user_tags) do
     table.insert(cmd_args, v)
   end