encoding/asn1: clarify use of SET suffix
This change clarifies the usage of the SET type name suffix. Previously
the documentation was somewhat confusing about where the suffix should
be used, and when used what it applied to. For instance the previous
language could be interpreted such that []exampleSET would be parsed as
a SEQUENCE OF SET, which is incorrect as the SET suffix only applies to
slice types, such as type exampleSET []struct{} which is parsed as a
SET OF SEQUENCE.
Change-Id: I74201d9969f931f69391c236559f66cb460569ec
GitHub-Last-Rev:
d0d2ddc587df4564a265c800efb9d8e204002624
GitHub-Pull-Request: golang/go#38543
Reviewed-on: https://go-review.googlesource.com/c/go/+/229078
Trust: Roland Shoemaker <roland@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>