doc: fixed small errors
Closes #88
https://github.com/cuelang/cue/pull/88
GitOrigin-RevId: ea72847a3a1b0314372f3eb6746688716ff0100c
Change-Id: I4093e992283d4f28aa13274f63e9dbedcb32c091
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/3047
Reviewed-by: Marcel van Lohuizen <mpvl@google.com>
authored by