design/go2draft-type-parameters: fix typo
design/go2draft-type-parameters: fix typo

Change-Id: If7434b7d2a111812047fd9c9cb95ff65aa2c50db
Reviewed-on: https://go-review.googlesource.com/c/proposal/+/239157
Reviewed-by: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>

golang/proposal,golang/proposal