doc: mention reflect anonymous struct visibiliy in go1.1 docs

[adg]

From the 1.1beta1 thread:

"Sanity check, am not seeing mention in the release notes of the change
to reflect to be able to go into anonymous fields of a struct, so that
encoding/json and friends can show fields from embedded types?

Oversight, dropped, ... ?"

[adg]

Comment 1:

It's these changes, I believe:
http://golang.org/change/a9fc9baa621b
http://golang.org/change/c15b9434ebaf
http://golang.org/change/71e709c69318

[robpike]

Comment 2:

Neither oversight nor dropped. The release notes are not complete. Far from it: they
make no attempt to describe bug fixes, only language changes, API changes, and major
performance-related changes.
We need to draw the line somewhere, and this issue falls on the wrong side. Completists
can check the Mercurial logs.

Labels changed: removed go1.1.

Status changed to WorkingAsIntended.