x/tools/analysis/passes/printf: fix error message for unsuppported %w

The current error message for calls to functions that not support %w
formatting directive does not explicitly say what is wrong nor why using
%w is wrong. This CL makes the message more direct.

Fixes golang/go#47690

Change-Id: I6e42ab725e5e3a989a8505ec230b4bb6218079ff
Reviewed-on: https://go-review.googlesource.com/c/tools/+/342111
Run-TryBot: Zvonimir Pavlinovic <zpavlinovic@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
Trust: Damien Neil <dneil@google.com>
Trust: Zvonimir Pavlinovic <zpavlinovic@google.com>

go/analysis/passes/printf/printf.go

@@ -590,12 +590,9 @@ func checkPrintf(pass *analysis.Pass, kind Kind, call *ast.CallExpr, fn *types.F
 		}
 		if state.verb == 'w' {
 			switch kind {
-			case KindNone, KindPrint:
+			case KindNone, KindPrint, KindPrintf:
 				pass.Reportf(call.Pos(), "%s does not support error-wrapping directive %%w", state.name)
 				return
-			case KindPrintf:
-				pass.Reportf(call.Pos(), "%s call has error-wrapping directive %%w, which is only supported for functions backed by fmt.Errorf", state.name)
-				return
 			}
 			if anyW {
 				pass.Reportf(call.Pos(), "%s call has more than one error-wrapping directive %%w", state.name)

go/analysis/passes/printf/testdata/src/a/a.go

@@ -333,7 +333,7 @@ func PrintfTests() {
 	_ = fmt.Errorf("%[2]w %[1]s", e, "x") // want `fmt.Errorf format %\[2\]w has arg "x" of wrong type string`
 	_ = fmt.Errorf("%w", "x")             // want `fmt.Errorf format %w has arg "x" of wrong type string`
 	_ = fmt.Errorf("%w %w", err, err)     // want `fmt.Errorf call has more than one error-wrapping directive %w`
-	fmt.Printf("%w", err)                 // want `fmt.Printf call has error-wrapping directive %w`
+	fmt.Printf("%w", err)                 // want `fmt.Printf does not support error-wrapping directive %w`
 	Errorf(0, "%w", err)
 }