Marks it as deprecated in lull with a comment, and removes the verbosity
toggle state from dill. Filtering should now happen at the edges where
%crud error messages get printed.
We don't remove it from lull just yet, because that would necessitate a
kelvin bump, even though the rest of this changeset doesn't.
The previous changes implementing the /~/name endpoint were breaking,
since we changed the type of `$action:eyre`. This commit keeps the /~/name
endpoint functional, but adds adapters to eyre scries that returns the old
`$action:eyre` type. These adapters and their associated intermediate types
can be removed the next time we burn a kelvin.
These haven't been in use for a long time (if ever), but are now fully
deprecated: if you want to receive system output, see dill's %logs task
instead.
Now that %logs exists, dill can delegate responsibility for printing
system output to outsiders (like the runtime, or the terminal handler
agent). Here, we remove dill's printing logic, which was still coupling
it to the default session and drum's expected semantics.
A dill %logs task can be used to open and close subscriptions to "system
output". Whenever dill receives a %text, %talk, or %crud task, it
considers this "system output", and passes it along to all %logs
subscribers.
Previously, if the pointer for a syntax error pointed to the end of the file
(and the file ended in a newline) the code snippet rendering would try to
display a line _beyond_ the end of the file, causing a crash.
Here, we detect that case, and display `<<end of file>>` instead.
(Originally merged through #5812, but got lost somewhere along the way.)
Fixes#6287.
