Correct task link in docs, closes #13388

Author: josevalim

lib/elixir/lib/task.ex

@@ -40,7 +40,7 @@ defmodule Task do
        as they are *always* sent. If you are not expecting a reply,
        consider using `Task.start_link/1` as detailed below.
 
-    2. async tasks link the caller and the spawned process. This
+    2. Async tasks link the caller and the spawned process. This
        means that, if the caller crashes, the task will crash
        too and vice-versa. This is on purpose: if the process
        meant to receive the result no longer exists, there is

lib/elixir/lib/task/supervisor.ex

@@ -152,7 +152,7 @@ defmodule Task.Supervisor do
   Starts a task that can be awaited on.
 
   The `supervisor` must be a reference as defined in `Supervisor`.
-  The task will still be linked to the caller, see `Task.async/3` for
+  The task will still be linked to the caller, see `Task.async/1` for
   more information and `async_nolink/3` for a non-linked variant.
 
   Raises an error if `supervisor` has reached the maximum number of
@@ -174,7 +174,7 @@ defmodule Task.Supervisor do
   Starts a task that can be awaited on.
 
   The `supervisor` must be a reference as defined in `Supervisor`.
-  The task will still be linked to the caller, see `Task.async/3` for
+  The task will still be linked to the caller, see `Task.async/1` for
   more information and `async_nolink/3` for a non-linked variant.
 
   Raises an error if `supervisor` has reached the maximum number of
@@ -196,7 +196,7 @@ defmodule Task.Supervisor do
   Starts a task that can be awaited on.
 
   The `supervisor` must be a reference as defined in `Supervisor`.
-  The task won't be linked to the caller, see `Task.async/3` for
+  The task won't be linked to the caller, see `Task.async/1` for
   more information.
 
   Raises an error if `supervisor` has reached the maximum number of
@@ -283,7 +283,7 @@ defmodule Task.Supervisor do
   Starts a task that can be awaited on.
 
   The `supervisor` must be a reference as defined in `Supervisor`.
-  The task won't be linked to the caller, see `Task.async/3` for
+  The task won't be linked to the caller, see `Task.async/1` for
   more information.
 
   Raises an error if `supervisor` has reached the maximum number of