go/doc: add // while wrapping a line comment in ToText
Currently, lineWrapper does not detect if it is printing a line comment or not.
Hence, while wrapping a comment, the new line does not get prefixed with a //.
We add logic to lineWrapper to detect this case and add // accordingly. Block
comments do not need any such handling.
Added tests for both cases.
Fixes #20929
Change-Id: I656037c2d865f31dd853cf9195f43ab7c6e6fc53
Reviewed-on: https://go-review.googlesource.com/c/go/+/163578
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Robert Griesemer <gri@golang.org>