Custom powerline glyphs aren't playing nicely with line height in webgl

line height 1.5

canvas

![image](https://user-images.githubusercontent.com/2193314/173695607-e446cd7b-1f0d-4d89-941b-483c3180332c.png)

webgl

![image](https://user-images.githubusercontent.com/2193314/173695646-01b76d7a-7180-45cf-9dc7-f0b3b566f39e.png)
