TODO: remove unneeded task

It's perfectly fine to use the new --skip option and give it
"cscope.out" as parameter. If there are big files in source tree in
general we will know their names in advance.
diff --git a/TODO b/TODO
index df7aa1a..4f86e06 100644
--- a/TODO
+++ b/TODO
@@ -1,9 +1,5 @@
 - Add option to disable changes to source code, allowing them only on comments
   and text files
 
-- Add option to ignore big files. The biggest issue is if you try to run
-  codespell with a file in the source code tree like cscope.out. I  don't know
-  if the best approach is to filter by name or by size
-
 BUGS
 ====