docs: Fix a PDF build error in bug-bisect.rst

It seems we can't have literal blocks in footnotes, which almost actually
makes some sense.  So just use basic ``monospace`` instead.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/admin-guide/bug-bisect.rst

@@ -66,9 +66,7 @@ Steps to do it:
 
 
 .. [#f1] You can, optionally, provide both good and bad arguments at git
-	 start::
-
-		git bisect start [BAD] [GOOD]
+	 start with ``git bisect start [BAD] [GOOD]``
 
 For further references, please read: