Update cabal-commands.rst (#10198)

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

doc/cabal-commands.rst

@@ -343,6 +343,7 @@ While this interface is intended to be used for scripting, it is an experimental
 Scripting example:
 
 ::
+
    $ ls $(cabal path --installdir)
    ...