_content/doc/effective_go: update for Go 1.26 and concise warning

Move warning note to top, make it concise and include release notes link.
Update 'new' section for Go 1.26 expression arguments - strictly
speaking, this doc is frozen so we don't need to update it. But since
`new` is a language builtin so mention it.

Change-Id: I3e857f5842d859b534726f2d639b6eea670f8dca
Reviewed-on: https://go-review.googlesource.com/c/website/+/764340
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Hyang-Ah Hana Kim <hyangah@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

1 files changed, 21 insertions, 20 deletions

diff --git a/_content/doc/effective_go.html b/_content/doc/effective_go.html
index 0b7389a8..e13f48b0 100644
--- a/_content/doc/effective_go.html
+++ b/_content/doc/effective_go.html
@@ -4,11 +4,21 @@
 	"Breadcrumb": true
 }-->
 
+<div class="Note">
+<strong>Note:</strong> This document was written for Go's release in 2009 and
+is not actively updated. While it remains a good guide for using the core language,
+it does not cover significant changes to the language (generics), ecosystem (modules),
+or libraries added since. See <a href="/issue/28782">issue 28782</a> for context.
+For a complete list of changes,
+see the <a href="/doc/devel/release">release notes</a>.
+</div>
+
 <h2 id="introduction">Introduction</h2>
 
 <p>
-Go is a new language.  Although it borrows ideas from
-existing languages,
+Go is an open-source programming language that focuses on simplicity, reliability,
+and efficiency, specifically designed to make it easy to build software at scale.
+Although it borrows ideas from existing languages,
 it has unusual properties that make effective Go programs
 different in character from programs written in its relatives.
 A straightforward translation of a C++ or Java program into Go
@@ -35,23 +45,7 @@ all of which you
 should read first.
 </p>
 
-<p>
-Note added January, 2022:
-This document was written for Go's
-release in 2009, and has not been updated significantly since.
-Although it is a good guide to understand how to use the language
-itself, thanks to the stability of the language, it says little
-about the libraries and nothing about significant changes to the
-Go ecosystem since it was written, such as the build system, testing,
-modules, and polymorphism.
-There are no plans to update it, as so much has happened and a large
-and growing set of documents, blogs, and books do a fine job of
-describing modern Go usage.
-Effective Go continues to be useful, but the reader should
-understand it is far from a complete guide.
-See <a href="/issue/28782">issue
-28782</a> for context.
-</p>
+
 
 <h3 id="examples">Examples</h3>
 
@@ -1006,13 +1000,20 @@ It's a built-in function that allocates memory, but unlike its namesakes
 in some other languages it does not <em>initialize</em> the memory,
 it only <em>zeros</em> it.
 That is,
-<code>new(T)</code> allocates zeroed storage for a new item of type
+<code>new(T)</code> allocates zeroed storage for a new variable of type
 <code>T</code> and returns its address, a value of type <code>*T</code>.
 In Go terminology, it returns a pointer to a newly allocated zero value of type
 <code>T</code>.
 </p>
 
 <p>
+Starting with Go 1.26, <code>new</code> also accepts an (value) expression as
+an argument, which specifies the initial value of the variable.
+For example, <code>new(int64(300))</code> allocates a new variable of type <code>int64</code>,
+initialized to 300, and returns its address.
+</p>
+
+<p>
 Since the memory returned by <code>new</code> is zeroed, it's helpful to arrange
 when designing your data structures that the
 zero value of each type can be used without further initialization.  This means a user of