doc: mention that reflect.SetMapIndex no longer panics
when deleting from a nil map. See issue 8051.
LGTM=r
R=golang-codereviews, r, khr
CC=golang-codereviews
https://golang.org/cl/96540051
diff --git a/src/pkg/reflect/value.go b/src/pkg/reflect/value.go
index 2cbda39..576cbc3 100644
--- a/src/pkg/reflect/value.go
+++ b/src/pkg/reflect/value.go
@@ -1620,6 +1620,7 @@
// SetMapIndex sets the value associated with key in the map v to val.
// It panics if v's Kind is not Map.
// If val is the zero Value, SetMapIndex deletes the key from the map.
+// Otherwise if v holds a nil map, SetMapIndex will panic.
// As in Go, key's value must be assignable to the map's key type,
// and val's value must be assignable to the map's value type.
func (v Value) SetMapIndex(key, val Value) {
