go/printer, gofmt: fix multi-line logic
A node spans multiple lines if the line difference
between start and end point is > 0 (rather than > 1).
Fixes some odd cases introduced by CL
5706055;
pointed out by dsymonds.
Added corresponding test case. The other change
in the .golden file reverts to the status before
the CL mentioned above and is correct.
gofmt -w src misc changes godoc.go back to where
it was before the CL mentioned above.
Fixes #3304.
R=dsymonds, rsc
CC=golang-dev
https://golang.org/cl/
5820044