[mode/meta] Add the mbox mode

mode/meta.js

@@ -87,6 +87,7 @@
     {name: "Modelica", mime: "text/x-modelica", mode: "modelica", ext: ["mo"]},
     {name: "MUMPS", mime: "text/x-mumps", mode: "mumps", ext: ["mps"]},
     {name: "MS SQL", mime: "text/x-mssql", mode: "sql"},
+    {name: "mbox", mime: "application/mbox", mode: "mbox", ext: ["mbox"]},
     {name: "MySQL", mime: "text/x-mysql", mode: "sql"},
     {name: "Nginx", mime: "text/x-nginx-conf", mode: "nginx", file: /nginx.*\.conf$/i},
     {name: "NSIS", mime: "text/x-nsis", mode: "nsis", ext: ["nsh", "nsi"]},