Fix typos (#14951)

Author: eksperimental

lib/mix/lib/mix/tasks/cmd.ex

@@ -26,7 +26,7 @@ defmodule Mix.Tasks.Cmd do
   Your shell will expand "lib/*" and then pass multiple arguments to
   `mix cmd`, which in turn passes them to `echo`. Note that, `mix cmd`
   by itself, does not perform any shell expansion. This means that,
-  if you invoke `mix cmd` programatically, as in:
+  if you invoke `mix cmd` programmatically, as in:
 
       Mix.Task.run("cmd", ["echo", "lib/*"])
 

lib/mix/lib/mix/tasks/xref.ex

@@ -47,7 +47,7 @@ defmodule Mix.Tasks.Xref do
   `lib/b.ex`, and `lib/c.ex` depend on will cause `lib/a.ex` to recompile.
   In other words, whenever you have a cycle, **a change to any file in the
   cycle will cause all compile-time deps to recompile**. Therefore, your
-  first priority to reduce constant recompilations is to remve them.
+  first priority to reduce constant recompilations is to remove them.
   You can spot them by running:
 
       $ mix xref graph --format cycles --label compile-connected