[Beta] Pressing Tab should create two spaces, not an actual tab

[gaearon]

Noticing this in sandboxes.

[harish-sethuraman]

While tab is pressed and we use left and right arrow to navigate it skips from start of tab to end and vice versa. Was it the same before? Any idea?

[gaearon]

This was an issue but we need to fix this to just emit spaces instead.