'byte' not marked

[Master811129]

Describe the bug
the app does not color 'byte'

To Reproduce
Steps to reproduce the behavior:

1. Go to 'Arduino Pro IDE'
2. type 'byte'
3. See the problem

Screenshots

Desktop (please complete the following information):

• OS:Win 10

like this one arduino/arduino-pro-ide#150

[ubidefeo]

I have merged this one into #380