Fix typo: RecursiveLock to ReentrantLock (JuliaLang#43192)

base/condition.jl

@@ -34,7 +34,7 @@ assert_havelock(l::AbstractLock, tid::Nothing) = concurrency_violation()
 This struct does not implement a real lock, but instead
 pretends to be always locked on the original thread it was allocated on,
 and simply ignores all other interactions.
-It also does not synchronize tasks; for that use a real lock such as [`RecursiveLock`](@ref).
+It also does not synchronize tasks; for that use a real lock such as [`ReentrantLock`](@ref).
 This can be used in the place of a real lock to, instead, simply and cheaply assert
 that the operation is only occurring on a single cooperatively-scheduled thread.
 It is thus functionally equivalent to allocating a real, recursive, task-unaware lock