spec: Go has no 'reference types'

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/8288044

doc/go_spec.html

@@ -1,6 +1,6 @@
<!--{
	"Title": "The Go Programming Language Specification",
	"Subtitle": "Version of March 22, 2013",
	"Subtitle": "Version of April 3, 2013",
	"Path": "/ref/spec"
}-->

@@ -837,9 +837,9 @@ <h3 id="Array_types">Array types</h3>
<h3 id="Slice_types">Slice types</h3>

<p>
A slice is a reference to a contiguous segment of an array and
contains a numbered sequence of elements from that array.  A slice
type denotes the set of all slices of arrays of its element type.
A slice is a descriptor for a contiguous segment of an array and
provides access to a numbered sequence of elements from that array.
A slice type denotes the set of all slices of arrays of its element type.
The value of an uninitialized slice is <code>nil</code>.
</p>

@@ -5197,8 +5197,6 @@ <h3 id="Allocation">Allocation</h3>
<h3 id="Making_slices_maps_and_channels">Making slices, maps and channels</h3>

<p>
Slices, maps and channels are reference types that do not require the
extra indirection of an allocation with <code>new</code>.
The built-in function <code>make</code> takes a type <code>T</code>,
which must be a slice, map or channel type,
optionally followed by a type-specific list of expressions.