doc/next: add release note for vet on Printf(s) with non-const s

Fixes #60529
Updates #68545

Change-Id: Ica048e4861f4de22deb7f42a1d76eb3151fee986
Reviewed-on: https://go-review.googlesource.com/c/go/+/631682
Auto-Submit: Alan Donovan <[email protected]>
Reviewed-by: Robert Findley <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

Author: adonovan

doc/next/3-tools.md

@@ -28,9 +28,14 @@ tests, fuzzers, benchmarks, and examples in test packages, such as
 malformed names, incorrect signatures, or examples that document
 non-existent identifiers. Some of these mistakes may cause tests not
 to run.
-
 This analyzer is among the subset of analyzers that are run by `go test`.
 
+The existing `printf` analyzer now reports a diagnostic for calls of
+the form `fmt.Printf(s)`, where `s` is a non-constant format string,
+with no other arguments. Such calls are nearly always a mistake
+as the value of `s` may contain the `%` symbol; use `fmt.Print` instead.
+See [#60529](/issue/60529).
+
 ### GOCACHEPROG
 
 The `cmd/go` internal binary and test caching mechanism can now be implemented