Support for time in headline

Org uses `org-agenda-search-headline-for-time` to search for time in headline when rendering the agenda time grid. This is enabled by default so an entry like

```
* TODO test 19:31-20:40
  <2021-10-11 Mon>
```
Would show up in the agenda as
```
category:      19:31-20:40 TODO test 
```

In my testing with `org-wild-notifier` these don't show up as alerts.