 
   Prints all callers of the given `MODULE`. Example:
 
-      mix xref callers MyMod
+      $ mix xref callers MyMod
 
   ## mix xref graph
 
   Prints a file dependency graph where an edge from `A` to `B` indicates
   that `A` (source) depends on `B` (sink).
 
-      mix xref graph --format stats
+      $ mix xref graph --format stats
 
   The following options are accepted:
 


      $ mix xref graph --label compile-direct
      lib/a.ex
      `-- lib/b.ex (compile)

  On the other hand, having direct compile time dependencies is not
  necessarily an issue. The biggest concern, as mentioned above, are the


      $ mix xref graph
      lib/a.ex
      └── lib/b.ex (compile)
      lib/b.ex
      └── lib/c.ex
      lib/c.ex

  This tree means that `lib/a.ex` depends on `lib/b.ex` at compile
