feat: Add width option

* This is relative to the size of the current split

lua/symbols-outline/config.lua

@@ -6,6 +6,7 @@ local defaults = {
     highlight_hovered_item = true,
     show_guides = true,
     position = 'right',
+    width = 25,
     auto_preview = true,
     show_numbers = false,
     show_relative_numbers = false,
@@ -64,6 +65,10 @@ function M.get_position_navigation_direction()
     end
 end
 
+function M.get_width_percentage()
+    return M.options.width / 100
+end
+
 function M.get_split_command()
     if M.options.position == 'left' then
         return "topleft vs"