internal/imports: update stdlib index for 1.17

    $ go run mkstdlib.go

Updates golang/go#38706.

Change-Id: I0ad28f7d5e1fec2d1ccc3bc0f01f43a7d2f0d817
Reviewed-on: https://go-review.googlesource.com/c/tools/+/344629
Run-TryBot: Akhil Indurti <[email protected]>
gopls-CI: kokoro <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Reviewed-by: Heschi Kreinick <[email protected]>
Trust: Dmitri Shuralyov <[email protected]>

Author: smasher164

internal/imports/mkstdlib.go

@@ -69,6 +69,7 @@ func main() {
 		mustOpen(api("go1.14.txt")),
 		mustOpen(api("go1.15.txt")),
 		mustOpen(api("go1.16.txt")),
+		mustOpen(api("go1.17.txt")),
 
 		// The API of the syscall/js package needs to be computed explicitly,
 		// because it's not included in the GOROOT/api/go1.*.txt files at this time.