`showHamburgerMenu: false` should use Application Menu

• I am on the latest Hyper.app version
• I have searched the issues of this repo and believe that this is not a duplicate

• OS version and name: Ubuntu 18.04
• Hyper.app version: 2.0.0
• Link of a Gist with the contents of your .hyper.js: (See below)
• Relevant information from devtools (CMD+ALT+I on macOS, CTRL+SHIFT+I elsewhere):
• The issue is reproducible in vanilla Hyper.app: Is Vanilla

Issue

I have the following in my .hyper.js. I am running Ubuntu 18.04 (GNOME) which supports "Application Menus"; however, when showHamburgerMenu is set to false, hyper does not utilize the Application Menu and instead uses context menus, despite not being context-specific.

    // if you're using a Linux setup which show native menus, set to false
    // default: `true` on Linux, `true` on Windows, ignored on macOS
    showHamburgerMenu: false,

Start by locating the showHamburgerMenu configuration and the Linux menu setup. Reproduce the behavior on Ubuntu 18.04 with showHamburgerMenu set to false, then verify that Hyper uses the desktop Application Menu instead of context menus.