fix: Avoid error when checking line content

lua/todoer/init.lua

@@ -120,7 +120,8 @@ local function setup_buffer_keymaps()
         end
 
         -- Check if the line is a TODO item and if it has content after the marker
-        local has_content = details.content and not vim.trim(details.content):empty()
+        -- Use string.match with %S to check for any non-whitespace character
+        local has_content = details.content and string.match(details.content, "%S")
 
         if details.is_todo and has_content then
             -- Case 1: Non-empty TODO line