Autocomplete/expansion broken on hyper 2.1.0-canary.2

• 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: OSX Mojave

• Hyper.app version: 2.1.0-canary.2

• Relevant information from devtools (CMD+ALT+I on macOS, CTRL+SHIFT+I elsewhere):

  Plugin hyper-snazzy (1.3.0) loaded.
  Plugin hyper-statusline (1.7.6) loaded.
  Plugin hyper-alt-click (0.1.1) loaded.
  Plugin hyperterm-tab-icons (1.1.0) loaded.
  Plugin hyperlinks (0.5.0) loaded.
  Plugin hyperfullscreen (1.0.1) loaded.

• The issue is reproducible in vanilla Hyper.app: Yes- removed all plugins and still present

Issue

Using TAB to complete adds invalid characters to the input. Consider this example where I hit TAB 3 times:

~
❯ cd htdocs/

~
❯ cd htdocs/
zsh: do you wish to see all 104 possibilities (26 lines)?

❯ cdcd htdocs/
Chart.js/                       fritzapi/                       modbus/                         syno-elk/

The 3rd time cd become cdcd. Here is another example how this looks (brbr):

Reproduce the issue in Hyper 2.1.0-canary.2 on macOS with plugins removed, using repeated TAB completion in zsh. Trace the terminal input and autocomplete handling from that reproduction; done means repeated TAB presses no longer duplicate characters such as “cdcd” or “brbr”.