str: change example to match function being explained.
[ccan] / ccan / idtree /
drwxr-xr-x   ..
lrwxrwxrwx 20 LICENSE -> ../../licenses/GPL-2
-rw-r--r-- 1354 _info
-rw-r--r-- 7907 idtree.c
-rw-r--r-- 2977 idtree.h
drwxr-xr-x - test