It makes more sense to handle escapes in configuration strings when we
parse them, rather than after-the-fact when we handle notifications that
use the relevant config options.
Do this in the proper backslash handler; rather than a naive string
replace which doesn't allow the backslash to be escaped (`\\n` => 0x5C0x0A
rather than 0x5C0x6E).
it to the proper backslash handler