doc/go1.4.html: rewrite first sentence to make it clearer

The grammar was atrocious, probably the victim of an editing error.

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://golang.org/cl/178910043

doc/go1.4.html

@@ -7,10 +7,10 @@
 <h2 id="introduction">Introduction to Go 1.4</h2>
 
 <p>
-The latest Go release, version 1.4, arrives as scheduled six months after 1.3
-and contains only one tiny language change,
-a possibly breaking change to the compiler,
-a backwards-compatible simple form of <code>for</code>-<code>range</code> loop.
+The latest Go release, version 1.4, arrives as scheduled six months after 1.3.
+It contains only one tiny language change,
+in the form of a backwards-compatible simple variant of <code>for</code>-<code>range</code> loop,
+and a possibly breaking change to the compiler involving methods on pointers-to-pointers.
 The release focuses primarily on implementation work, improving the garbage collector
 and preparing the ground for a fully concurrent collector to be rolled out in the
 next few releases.
@@ -20,7 +20,7 @@ <h2 id="introduction">Introduction to Go 1.4</h2>
 There are some new tools available including support in the <code>go</code> command
 for build-time source code generation.
 The release also adds support for ARM processors on Android and Native Client (NaCl)
-and AMD64 on Plan 9.
+and for AMD64 on Plan 9.
 As always, Go 1.4 keeps the <a href="/doc/go1compat.html">promise
 of compatibility</a>,
 and almost everything