[release-branch.go1.12] doc: don't use "go tool vet" as an example

Updates #30199

Change-Id: Ib4586e3facb8c0985c8882482d94843b648b9d2f
Reviewed-on: https://go-review.googlesource.com/c/162257
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
(cherry picked from commit ffd096db)
Reviewed-on: https://go-review.googlesource.com/c/162238Reviewed-by: Andrew Bonventre <andybons@golang.org>

doc/cmd.html

@@ -18,10 +18,8 @@ underlying binary with arguments appropriate to package-level processing.
 
 <p>
 The programs can also be run as stand-alone binaries, with unmodified arguments,
-using the go <code>tool</code> subcommand, such as <code>go tool vet</code>.
-This style of invocation allows, for instance, checking a single source file
-rather than an entire package: <code>go tool vet myprogram.go</code> as
-compared to <code>go vet mypackage</code>.
+using the go <code>tool</code> subcommand, such as <code>go tool cgo</code>.
+For most commands this is mainly useful for debugging.
 Some of the commands, such as <code>pprof</code>, are accessible only through
 the go <code>tool</code> subcommand.
 </p>
@@ -76,7 +74,7 @@ and rewrites them to use newer ones.</td>
 </tr>
 
 <tr>
-<td><a href="/cmd/go/">fmt</a></td>
+<td><a href="/cmd/gofmt/">fmt</a></td>
 <td>&nbsp;&nbsp;&nbsp;&nbsp;</td>
 <td>Fmt formats Go packages, it is also available as an independent <a href="/cmd/gofmt/">
 gofmt</a> command with more general options.</td>

doc/install-source.html

@@ -349,15 +349,7 @@ provides <b>essential setup instructions</b> for using the Go tools.
 <p>
 The source code for several Go tools (including <a href="/cmd/godoc/">godoc</a>)
 is kept in <a href="https://golang.org/x/tools">the go.tools repository</a>.
-To install all of them, run the <code>go</code> <code>get</code> command:
-</p>
-
-<pre>
-$ go get golang.org/x/tools/cmd/...
-</pre>
-
-<p>
-Or if you just want to install a specific command (<code>godoc</code> in this case):
+To install one of the tools (<code>godoc</code> in this case):
 </p>
 
 <pre>
@@ -374,16 +366,6 @@ You must also have a workspace (<code>GOPATH</code>) set up;
 see <a href="/doc/code.html">How to Write Go Code</a> for the details.
 </p>
 
-<p>
-<b>Note</b>: The <code>go</code> command will install the <code>godoc</code>
-binary to <code>$GOROOT/bin</code> (or <code>$GOBIN</code>) and the
-<code>cover</code> and <code>vet</code> binaries to
-<code>$GOROOT/pkg/tool/$GOOS_$GOARCH</code>.
-You can access the latter commands with
-"<code>go</code> <code>tool</code> <code>cover</code>" and
-"<code>go</code> <code>tool</code> <code>vet</code>".
-</p>
-
 <h2 id="community">Community resources</h2>
 
 <p>