Handle \left and \right commands

`\left` and `\right` commands used with `listings`-`fancyverb`
interface, even when properly registered with `morefvcmdparams` lead to
"Missing delimiter" error.

Probably they use their argument in some special way incompatible with
how `listings` is passing arguments to `fvcmdparams`-registered
commands.

We can make them work by wrapping them with "ordinary" document level
commands. Since those commands should work as originals, we just
redefine originals locally inside formatted cells that use `listings`.

mmacells.sty

@@ -232,9 +232,18 @@
         \clist_put_left:NV
           \l_mmacells_lst_keyval_clist
           \l_mmacells_formatted_lst_keyval_clist
+
+        % \left and \right commands don't work properly with listings-fancyverb
+        % interface, we can make them work by redefining them as "ordinary"
+        % document-level functions.
+        \RenewDocumentCommand \left { m } { \__mmacells_tex_left:w ##1 }
+        \RenewDocumentCommand \right { m } { \__mmacells_tex_right:w ##1 }
       }
   }
 
+\cs_new_eq:NN \__mmacells_tex_left:w \left
+\cs_new_eq:NN \__mmacells_tex_right:w \right
+
 \cs_new_protected_nopar:Npn \__mmacells_prepare_lst_keyval:
   {
     \clist_put_left:Nn \l_mmacells_lst_keyval_clist { fancyvrb=true }
@@ -714,6 +723,8 @@
     morefvcmdparams=\Big 1,
     morefvcmdparams=\bigg 1,
     morefvcmdparams=\Bigg 1,
+    morefvcmdparams=\left 1,
+    morefvcmdparams=\right 1,
   }