_content: change 'go get' to 'go install' where appropriate

For golang/go#43684

Change-Id: Ifdb0695d15961150960f7be3eb0fb44ac1f0d4d2
Reviewed-on: https://go-review.googlesource.com/c/website/+/355249
Trust: Jay Conrod <jayconrod@google.com>
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

_content/dl.tmpl

@@ -103,7 +103,7 @@ $(document).ready(function() {
 			<p>This is an <b>unstable</b> version of Go. Use with caution.</p>
 			<p>If you already have Go installed, you can install this version by running:</p>
 <pre>
-go get golang.org/dl/{{.Version}}
+go install golang.org/dl/{{.Version}}@latest
 </pre>
 			<p>Then, use the <code>{{.Version}}</code> command instead of the <code>go</code> command to use {{.Version}}.</p>
 		{{end}}

_content/doc/go-get-install-deprecation.md

@@ -8,9 +8,9 @@
 Starting in Go 1.17, installing executables with `go get` is deprecated.
 `go install` may be used instead.
 
-In a future Go release, `go get` will no longer build packages; it will only
+In Go 1.18, `go get` will no longer build packages; it will only
 be used to add, update, or remove dependencies in `go.mod`. Specifically,
-`go get` will act as if the `-d` flag were enabled.
+`go get` will always act as if the `-d` flag were enabled.
 
 ## What to use instead
 
@@ -40,7 +40,7 @@ In order to avoid ambiguity, when `go install` is used with a version suffix,
 all arguments must refer to `main` packages in the same module at the same
 version. If that module has a `go.mod` file, it must not contain directives like
 `replace` or `exclude` that would cause it to be interpreted differently if it
-were the main module.
+were the main module. The module's `vendor` directory is not used.
 
 See [`go install`](/ref/mod#go-install) for details.
 

_content/doc/index.html

@@ -195,7 +195,7 @@ A major version update can be very disruptive to your module's users because it
 
 <h4 id="modules-publishing"><a href="/doc/modules/publishing">Publishing a module</a></h4>
 <p>
-When you want to make a module available for other developers, you publish it so that it's visible to Go tools. Once you've published the module, developers importing its packages will be able to resolve a dependency on the module by running commands such as go get.
+When you want to make a module available for other developers, you publish it so that it's visible to Go tools. Once you've published the module, developers importing its packages will be able to resolve a dependency on the module by running commands such as <code>go get</code>.
 </p>
 
 <h4 id="modules-version-numbers"><a href="/doc/modules/version-numbers">Module version numbering</a></h4>

_content/doc/install/source.html

@@ -398,19 +398,9 @@ To install one of the tools (<code>godoc</code> in this case):
 </p>
 
 <pre>
-$ go get golang.org/x/tools/cmd/godoc
+$ go install golang.org/x/tools/cmd/godoc@latest
 </pre>
 
-<p>
-To install these tools, the <code>go</code> <code>get</code> command requires
-that <a href="#git">Git</a> be installed locally.
-</p>
-
-<p>
-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>
-
 <h2 id="community">Community resources</h2>
 
 <p>
@@ -504,8 +494,8 @@ you must set <code>GOPATH</code> to another location to avoid conflicts.
 <p>
 The directory where executables outside the Go distribution are installed
 using the <a href="/cmd/go">go command</a>. For example,
-<code>go get golang.org/x/tools/cmd/godoc</code> downloads, builds, and
-installs <code>$GOBIN/godoc</code>. By default, <code>$GOBIN</code> is
+<code>go install golang.org/x/tools/cmd/godoc@latest</code> downloads, builds,
+and installs <code>$GOBIN/godoc</code>. By default, <code>$GOBIN</code> is
 <code>$GOPATH/bin</code> (or <code>$HOME/go/bin</code> if <code>GOPATH</code>
 is not set). After installing, you will want to add this directory to
 your <code>$PATH</code> so you can use installed tools.