add minimal docstrings

src/internals.jl

@@ -24,7 +24,9 @@ end
 Base.schedule(t::StableTask) = (schedule(t.t); t)
 Base.schedule(t, val; error=false) = (schedule(t.t, val; error); t)
 
-
+"""
+Similar to `Threads.@spawn` but type-stable. Creates a `Task` and schedules it to run on any available thread in the `:default` threadpool.
+"""
 macro spawn(ex)
     letargs = _lift_one_interp!(ex)
 
@@ -55,6 +57,10 @@ macro spawn(ex)
     end
 end
 
+"""
+Similar to `StableTasks.@spawn` but creates a **sticky** `Task` and schedules it to run on the thread with the given id (`thrdid`).
+The task is guaranteed to stay on this thread (it won't migrate to another thread). 
+"""
 macro spawnat(thrdid, ex)
     letargs = _lift_one_interp!(ex)