Update Condition() docs to highlight return value and error (#50688)

Author: freemin7

base/condition.jl

@@ -175,8 +175,9 @@ isempty(c::GenericCondition) = isempty(c.waitq)
 
 Create an edge-triggered event source that tasks can wait for. Tasks that call [`wait`](@ref) on a
 `Condition` are suspended and queued. Tasks are woken up when [`notify`](@ref) is later called on
-the `Condition`. Edge triggering means that only tasks waiting at the time [`notify`](@ref) is
-called can be woken up. For level-triggered notifications, you must keep extra state to keep
+the `Condition`. Waiting on a condition can return a value or raise an error if the optional arguments
+of [`notify`](@ref) are used. Edge triggering means that only tasks waiting at the time [`notify`](@ref)
+is called can be woken up. For level-triggered notifications, you must keep extra state to keep
 track of whether a notification has happened. The [`Channel`](@ref) and [`Threads.Event`](@ref) types do
 this, and can be used for level-triggered events.