internal/imports: update stdlib index for Go 1.20

For golang/go#38706.

Change-Id: Iefd858ec1848481a26d6bb88076ff8a3c2f8a818
Reviewed-on: https://go-review.googlesource.com/c/tools/+/464875
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
gopls-CI: kokoro <noreply+kokoro@google.com>
Auto-Submit: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Gopher Robot <gobot@golang.org>
diff --git a/internal/imports/zstdlib.go b/internal/imports/zstdlib.go
index a03ff2c..31a7594 100644
--- a/internal/imports/zstdlib.go
+++ b/internal/imports/zstdlib.go
@@ -11108,5 +11108,8 @@
 		"Pointer",
 		"Sizeof",
 		"Slice",
+		"SliceData",
+		"String",
+		"StringData",
 	},
 }