Space-k exists in documentation but not in the editor.

[txtyash]

There's a feature to look up the help for the word under the cursor(Space-k). It is not actually present inside the editor but only in the documentation and please explicitly state in the documentation that space has to be pressed to enter space mode.

[archseer]

It's K in 0.4.1 and was changed to space+k in master. A new release will go out soon to fix the discrepancy.