Remove task with at method.

TODO.md

@@ -3,7 +3,6 @@
 ### Important
 - .help() seems really slow on big piece of code (for example RedBaron("baron/grammator.py").read())("dict")[0].help() is suuuuuuuuuuuuuuuuper slow)
-- .at() return the first item starting at line X
 - .rename() (name -> value, def/class -> name)
 - .replace() expect a whole valid python program. This could be fixed by look at "on_attribute" and resetting itself like that.