doc/go2draft-type-parameters: fix type parameter typo

Change-Id: Icff5f64231f937e9261c42030766e21768f5d430
Reviewed-on: https://go-review.googlesource.com/c/proposal/+/240340
Reviewed-by: Rob Pike <r@golang.org>
diff --git a/design/go2draft-type-parameters.md b/design/go2draft-type-parameters.md
index 39aac42..9669547 100644
--- a/design/go2draft-type-parameters.md
+++ b/design/go2draft-type-parameters.md
@@ -2867,7 +2867,7 @@
 func (m *Map(K, V)) Find(k K) (V, bool) {
 	pn := m.find(k)
 	if *pn == nil {
-		var zero val // see the discussion of zero values, above
+		var zero V // see the discussion of zero values, above
 		return zero, false
 	}
 	return (*pn).v, true