[doc] fix key used in the hook example
The hook's regid is check_no_subsidiary_cycle.
--- a/doc/book/devrepo/repo/hooks.rst Wed May 22 11:32:09 2019 +0200
+++ b/doc/book/devrepo/repo/hooks.rst Wed May 22 11:34:08 2019 +0200
@@ -153,7 +153,7 @@
Here, we call :func:`add_data` so that we will simply accumulate eids of
entities to check at the end in a single `CheckSubsidiaryCycleOp`
operation. Values are stored in a set associated to the
-'subsidiary_cycle_detection' transaction data key. The set initialization and
+'check_no_subsidiary_cycle' transaction data key. The set initialization and
operation creation are handled nicely by :func:`add_data`.
A more realistic example can be found in the advanced tutorial chapter