================================================================================
fref
================================================================================
\fref{eq:foo}
--------------------------------------------------------------------------------
(document
  (fref
    (cs)
    (group (l) (text) (r))))

================================================================================
fref with optional parameter
================================================================================
\fref[wibble]{eq:foo}
--------------------------------------------------------------------------------
(document
  (fref
    (cs)
    (brack_group (lbrack) (text) (rbrack))
    (group (l) (text) (r))))

================================================================================
Fref
================================================================================
\Fref{eq:foo}
--------------------------------------------------------------------------------
(document
  (fref
    (cs)
    (group (l) (text) (r))))

================================================================================
Fref with optional parameter
================================================================================
\Fref[wibble]{eq:foo}
--------------------------------------------------------------------------------
(document
  (fref
    (cs)
    (brack_group (lbrack) (text) (rbrack))
    (group (l) (text) (r))))