docs/stdlib.md: clarify the change in the go.alternateTools section

And include a link to the gopls.

Change-Id: Ia98cc3797154bd60497f3efb901fce782007835b
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/257599
Trust: Hyang-Ah Hana Kim <hyangah@gmail.com>
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
diff --git a/docs/stdlib.md b/docs/stdlib.md
index 746fc4c..fea0e40 100644
--- a/docs/stdlib.md
+++ b/docs/stdlib.md
@@ -6,25 +6,36 @@
 (See [golang/go#32394](https://github.com/golang/go/issues/32394).)
 
 Then, you need to configure the workspace, by placing the following in `src/.vscode/settings.json`.
+[Command Palette](https://code.visualstudio.com/docs/getstarted/userinterface#_command-palette)
+-> `Preferences: Open Workspace Settings (JSON)` will open the setting file.
 
 ```json5
 {
-    // Use the local go tool. This needs to be built with make.bash.
-    "go.alternateTools": {
-        "go": "~/godev/bin/go"
-    },
-    // Build a separate set of tools. For golang/vscode-go#294.
-    "go.toolsGopath": "~/.vscode/godev",
-    // Don't reformat HTML files since we have a custom style.
-    "html.format.enable": false,
+  // Use the local go tool. This needs to be built with make.bash.
+  "go.alternateTools": {
+    "go": "~/godev/bin/go"
+  },
+
+  //
+  // Below is optional.
+  //
+  // Build a separate set of tools. For golang/vscode-go#294.
+  "go.toolsGopath": "~/.vscode/godev",
+  // Don't reformat HTML files since we have a custom style.
+  "html.format.enable": false
 }
 ```
 
 The above assumes the Go tree is checked out at `~/godev`. If your Go tree is somewhere else, modify
-`go.alternateTools.go` accordingly.
+`go.alternateTools.go` to point to the go *binary* accordingly. Many underlying tools
+including `gopls` invoke the go command (`go list`, etc), so we assume the binary isn't 
+completely broken.
 
 You can add `.vscode` to `.git/info/exclude` to avoid risking checking `settings.json` into git.
 
+The Go language server ([`gopls`](https://golang.org/s/gopls)) works for developing the standard
+library. To enable it, please read our [`gopls` documentation](gopls.md).
+
 If you see an "inconsistent vendoring" error, please report it at
 [golang/go#40250](https://github.com/golang/go/issues/40250).