[release] docs/nightly: move README.md.nightly to its own directory

Hana, let me know if you don't like this change. I was just thinking
that it might be confusing for people to see 2 READMEs and 2 CHANGELOGs
at the top level. This way, we can keep this documentation separate.

Also modified the nightly README so that the information is a little
more up-to-date.

Change-Id: I6086ab0950d0fb56d3d5dfd789b45ca88985b7d7
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/236281
Reviewed-by: Hyang-Ah Hana Kim <[email protected]>
(cherry picked from commit 8aa661c)
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/236924

Author: stamblerre

docs/nightly.md

@@ -1,6 +1,8 @@
 # Go Nightly
 
-This master branch of this extension is built and published nightly through the [Go Nightly](https://marketplace.visualstudio.com/items?itemName=golang.go-nightly). If you're interested in testing new features and bug fixes, you may be interested in switching to the Go Nightly extension. Also, if you file an issue, we may suggest trying out the fix in Go Nightly.
+This master branch of this extension is built and published nightly through the [Go Nightly]. If you're interested in testing new features and bug fixes, you may be interested in switching to the Go Nightly extension. Also, if you file an issue, we may suggest trying out the fix in Go Nightly.
+
+The [Changelog](nightly/CHANGELOG.md) and [README](nightly/README.md) for [Go Nightly] can be found in the [docs/nightly](nightly/) directory.
 
 If you try out Go Nightly, please file issues when you notice bugs. You can also join the maintainers in the [#vscode-dev](https://gophers.slack.com/archives/CUWGEKH5Z) channel on the [Gophers Slack](https://invite.slack.golangbridge.org/).
 
@@ -19,3 +21,5 @@ Pre-releases of the Go extension will be made available on the [Releases page](h
 3) If prompted, reload VS Code.
 
 **Note**: If you install an extension from a VSIX file, you will stop receiving automatic prompts when updates are released.
+
+[Go Nightly]: https://marketplace.visualstudio.com/items?itemName=golang.go-nightly

docs/nightly/CHANGELOG.md

@@ -0,0 +1,4 @@
+## 2020.3.x
+* Set the extension name for VS Code Go Nightly(`go-nightly`).
+* Pick up the pre-release version of `gopls` if available.
+* Disabled the telemetry report for VS Code Go.

docs/nightly/README.md

@@ -0,0 +1,14 @@
+# Go Nightly for VS Code
+
+> ### **ATTENTION: This is the *preview* version of the [VS Code Go extension](https://github.com/golang/vscode-go), used for early feedback and testing.**
+> It is published nightly and contains previews of new features and bug fixes that are still under review or being tested. Therefore, this extension can be broken or unstable at times. If you are looking for the stable version,
+please install [the default VS Code Go extension](https://marketplace.visualstudio.com/items?itemName=golang.go) instead.
+>
+> **NOTE: The stable Go extension (`golang.Go`) cannot be used at the same time as the preview Go Nightly extension (`golang.go-nightly`)**. If you have installed both extensions, you **must disable or uninstall** one of them. For further guidance, read the [documentation on how to disable an extension](https://code.visualstudio.com/docs/editor/extension-gallery#_disable-an-extension).
+
+> ### **Differences between Go and Go Nightly**
+>
+> * Go Nightly is released more frequently than the stable version (once per weekday).
+> * Go Nightly includes features and bug fixes that are not yet finalized.
+> * Go Nightly may use pre-release versions of tools (such as `gopls`) instead of released versions.
+> * For more information about Go Nightly, read the [Go Nightly](../nightly.md) documentation.