x/website: incorrect synopsis for index/suffixarray

[afq984]

What did you do?

Visit https://golang.org/pkg/index/ and https://golang.org/pkg

What did you expect to see?

What did you see instead?

Git bisect says https://go-review.googlesource.com/c/website/+/296378

[gopherbot]

Change https://golang.org/cl/311089 mentions this issue: internal/pkgdoc: fix synopsis pkg name == dir name matching

[seankhliao]

duplicate of #45042 ?

[afq984]

@seankhliao oops, yes, they look like the same problem