_content/blog/go1.18beta1: add generics to headline
_content/blog/go1.18beta1: add generics to headline

Change-Id: Icea98fad0e358fbbd01554a6c816a2e57b2150d7
Reviewed-on: https://go-review.googlesource.com/c/website/+/371895
Trust: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>
Run-TryBot: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>
Reviewed-by: Steve Francia <8bbf1ab1cb1a07dcbcda348213c00549e847f42d@google.com>

golang/website,golang/website,golang/website,golang/website,golang/website,golang/website,golang/website