doc/initial, doc/next: add draft notice to introduction

Go release notes always start out as a draft with a clear notice.
That notice is removed when the final release (go1.N.0) is made.
For example, the last time was in CL 562255.

Add this to the Go 1.23 draft and to the future fragment template.

Also switch to the main pkg.go.dev instance and use a relative issue
link in 3-tools.md while here.

For #64169.
For #65614.

Change-Id: I16bc0fa8a3a43ee7a9edd7fa253999041f1892e2
Reviewed-on: https://go-review.googlesource.com/c/go/+/587415
Reviewed-by: Jonathan Amsterdam <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
TryBot-Bypass: Dmitri Shuralyov <[email protected]>
Auto-Submit: Dmitri Shuralyov <[email protected]>

Author: dmitshur

doc/initial/1-intro.md

@@ -8,5 +8,7 @@ set fixed-width phrases with non-fixed-width spaces, as in
   main ul li { margin: 0.5em 0; }
 </style>
 
-## Introduction to Go 1.XX {#introduction}
+## DRAFT RELEASE NOTES — Introduction to Go 1.N {#introduction}
 
+**Go 1.N is not yet released. These are work-in-progress release notes.
+Go 1.N is expected to be released in {Month} {Year}.**

doc/next/1-intro.md

@@ -8,5 +8,7 @@ set fixed-width phrases with non-fixed-width spaces, as in
   main ul li { margin: 0.5em 0; }
 </style>
 
-## Introduction to Go 1.23 {#introduction}
+## DRAFT RELEASE NOTES — Introduction to Go 1.23 {#introduction}
 
+**Go 1.23 is not yet released. These are work-in-progress release notes.
+Go 1.23 is expected to be released in August 2024.**

doc/next/3-tools.md

@@ -3,7 +3,7 @@
 ### Go command {#go-command}
 
 Setting the `GOROOT_FINAL` environment variable no longer has an effect
-([#62047](https://go.dev/issue/62047)).
+([#62047](/issue/62047)).
 Distributions that install the `go` command to a location other than
 `$GOROOT/bin/go` should install a symlink instead of relocating
 or copying the `go` binary.
@@ -15,7 +15,7 @@ that would be obtained in an empty environment with no prior uses of the `-w` fl
 ### Vet {#vet}
 
 The `go vet` subcommand now includes the
-[stdversion](https://beta.pkg.go.dev/golang.org/x/tools/go/analysis/passes/stdversion)
+[stdversion](https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/stdversion)
 analyzer, which flags references to symbols that are too new for the version
 of Go in effect in the referring file. (The effective version is determined
 by the `go` directive in the file's enclosing `go.mod` file, and