[propagate_anchors] Fix propagating cursive anchors

[khaledhosny]

Cursive anchors begin with “entry”/“exit” not end with it. This does not matter for the common case where the anchor name is only “entry” or “exit”, but it breaks if the anchor name has a suffix.

[khaledhosny]

The regression test failures all involve #exit or #entry anchors. These will be ignored by the feature writer anyway, so there is no functional difference (it is questionable whether we should even be propagated them, but that is an existing issue since we were already propagating some of them).