nvim: make signature in statusline independent of window width

doesn't make sense with global statusline. 😊

.config/nvim/lua/my/functions.lua

@@ -134,7 +134,7 @@ function M.lsp_status()
 end
 
 function M.lsp_sig_status()
-    local width = vim.api.nvim_win_get_width(0) / 2
+    local width = vim.o.columns / 3
     return require('lsp_signature').status_line(width).label
 end