[FAB-9942] Remove :ref: to non-existent "binaries" lbl

In prereqs.rst, change reference to non-existent "binaries"
label to a simple verbatim rendering, since it refers to the
command by that name.

Change-Id: I39bb36f3f404f74be497b3e5d97f66891563734f
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>

Author: rpjday

docs/source/prereqs.rst

@@ -148,7 +148,7 @@ difficulties with operations involving the ``make`` and ``docker``
 commands.
 
 On Windows 10 you should use the native Docker distribution and you
-may use the Windows PowerShell. However, for the :ref:`binaries`
+may use the Windows PowerShell. However, for the ``binaries``
 command to succeed you will still need to have the ``uname`` command
 available. You can get it as part of Git but beware that only the
 64bit version is supported.