website(aws): link directly to lambda "Runtime" defininition
website(aws): link directly to lambda "Runtime" defininition

Previously we linked to the whole request body definition for valid values of `runtime`.

Now we link directly to the docs for `Runtime`, which will hopefully make it easier to find the valid values.

This fixes #4570.
ClementCunin/terraform-provider-aws,nbaztec/terraform-provider-aws,ashinohara/terraform-provider-aws,ClementCunin/terraform-provider-aws,kjmkznr/terraform-provider-aws,charles-at-geospock/terraform-provider-aws,ashinohara/terraform-provider-aws,kjmkznr/terraform-provider-aws,Ninir/terraform-provider-aws,Ninir/terraform-provider-aws,terraform-providers/terraform-provider-aws,nbaztec/terraform-provider-aws,nbaztec/terraform-provider-aws,ClementCunin/terraform-provider-aws,terraform-providers/terraform-provider-aws,charles-at-geospock/terraform-provider-aws,Ninir/terraform-provider-aws,kjmkznr/terraform-provider-aws,terraform-providers/terraform-provider-aws,kjmkznr/terraform-provider-aws,ashinohara/terraform-provider-aws,terraform-providers/terraform-provider-aws,Ninir/terraform-provider-aws,nbaztec/terraform-provider-aws,charles-at-geospock/terraform-provider-aws,charles-at-geospock/terraform-provider-aws,ashinohara/terraform-provider-aws,ClementCunin/terraform-provider-aws