src/goInstallTools: add reference for incorrect PATH issue

When VSCode fails to load the login shell environment
within a hard-coded time limit, VSCode starts the extension
without complete PATH environment. As a result, the Go
extension fails to find go.

Until VSCode finds a way to address the issue, provide
users the link to the issue - so they can quickly find
the temporary workaround ('Reload the window').

Fixes golang/vscode-go#971

Change-Id: I94a1291f24a5a53edfcdf6c8e62b468f91396268
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/276492
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Suzy Mueller <suzmue@golang.org>
Trust: Suzy Mueller <suzmue@golang.org>
Trust: Hyang-Ah Hana Kim <hyangah@gmail.com>
diff --git a/src/goInstallTools.ts b/src/goInstallTools.ts
index 05ebc4f..5c64e84 100644
--- a/src/goInstallTools.ts
+++ b/src/goInstallTools.ts
@@ -514,18 +514,15 @@
 let suggestedDownloadGo = false;
 
 async function suggestDownloadGo() {
+	const msg = `Failed to find the "go" binary in either GOROOT(${getCurrentGoRoot()}) or PATH(${envPath}).` +
+			`Check PATH, or Install Go and reload the window. ` +
+			`If PATH isn't what you expected, see https://github.com/golang/vscode-go/issues/971`;
 	if (suggestedDownloadGo) {
-		vscode.window.showErrorMessage(
-			`Failed to find the "go" binary in either GOROOT(${getCurrentGoRoot()}) or PATH(${envPath}).`
-		);
+		vscode.window.showErrorMessage(msg);
 		return;
 	}
 
-	const choice = await vscode.window.showErrorMessage(
-		`Failed to find the "go" binary in either GOROOT(${getCurrentGoRoot()}) or PATH(${envPath}). ` +
-		`Check PATH, or Install Go and reload the window.`,
-		'Go to Download Page'
-	);
+	const choice = await vscode.window.showErrorMessage(msg, 'Go to Download Page');
 	if (choice === 'Go to Download Page') {
 		vscode.env.openExternal(vscode.Uri.parse('https://golang.org/dl/'));
 	}