doc/go1.12: release notes for "go doc -all"

Change-Id: If65518c76a865c03266be76b1c21c76e1c8b4763
Reviewed-on: https://go-review.googlesource.com/c/153828Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

doc/go1.12.html

@@ -220,7 +220,7 @@ for {
   printing and variable location information.
 </p>
 
-<h3 id="godoc">Godoc</h3>
+<h3 id="godoc"><code>godoc</code> and <code>go</code> <code>doc</code></h3>
 
 <p>
   In Go 1.12, <code>godoc</code> no longer has a command-line interface and
@@ -228,6 +228,12 @@ for {
   for command-line help output instead.
 </p>
 
+<p><!-- CL 141977 -->
+  <code>go</code> <code>doc</code> now supports the <code>-all</code> flag,
+  which will cause it to print all exported APIs and their documentation,
+  similarly to what the <code>godoc</code> command line used to do.
+</p>
+
 <h3 id="trace">Trace</h3>
 
 <p><!-- CL 60790 -->
@@ -276,7 +282,6 @@ for {
 <!-- CL 116275: https://golang.org/cl/116275: cmd/compile: avoid string allocations when map key is struct or array literal -->
 <!-- CL 142717: https://golang.org/cl/142717: cmd/compile: remove obsolete "safe" mode -->
 <!-- CL 146058: https://golang.org/cl/146058: It is invalid to convert a nil unsafe.Pointer to uintptr and back, with arithmetic.: cmd/compile: assume unsafe pointer arithmetic generates non-nil results -->
-<!-- CL 141977: https://golang.org/cl/141977: cmd/doc: add -all flag to print all documentation for package -->
 <!-- CL 146898: https://golang.org/cl/146898: cmd/link, runtime: add initial cgo support for ppc64 -->
 <!-- CL 115677: https://golang.org/cl/115677: cmd/vet: check embedded field tags too -->
 <dl id="bufio"><dt><a href="/pkg/bufio/">bufio</a></dt>